Name is Mark, and I live at Reno. Wheeling since 1976, like 4x4s, ATVs, dirt bikes and my beloved, and sometimes hated, 1981 CJ8 Scrambler. Interested in all things Jeep!
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Owner: MegatronAdded: 27 September 2013 - 08:56 AM
Owner: MegatronAdded: 25 September 2013 - 07:37 AM
Owner: Moses LudelAdded: 15 September 2013 - 01:16 PM
Owner: biggman100Added: 22 September 2013 - 05:22 PM
Owner: Moses LudelAdded: 15 September 2013 - 08:42 AM
Posted by RareCJ8 on 09 April 2013 - 09:46 PM
Name is Mark, and I live at Reno. Wheeling since 1976, like 4x4s, ATVs, dirt bikes and my beloved, and sometimes hated, 1981 CJ8 Scrambler. Interested in all things Jeep!
Posted by Moses Ludel on 27 July 2013 - 01:16 PM
All good points, Megatron, each deserves an explanation, so here we go...I'll begin by sharing that I ran a four-wheel alignment rack at a GMC truck dealership in the mid-'80s, the era of both beam front axle 4x4s and IFS 2WD and 4WD front ends. For fifteen years prior to that, I had been doing alignment with far less equipment than that new Hunter four-wheel, electronic light beam rack. Fifteen years after the dealership stint, I taught wheel alignment at the adult vocational training level and merged my varied equipment experiences, which reflect in what I'm now sharing.
It's great to use precision four-wheel alignment equipment. However, "computer" alignment equipment is also limited in many ways. For example, you describe aftermarket wheels, suspension and tires, and you're right, of the three (assuming the suspension kit is as adjustable as yours), the wheel offset is the most critical modification. Because your truck falls outside the OEM guidelines built into the software for modern alignment equipment, many shops will avoid doing your truck's alignment.
Reasons for refusal include "liability", "unpredictable results" and "possibility of abnormal tire wear"—regardless of the alignment procedure. In many cases, the shop simply doesn't know what they can do to address or compensate for your modifications...After all, this is the era of plug-and-play. Follow the flow charts or stare at the computer screen or scanner. Wait long enough, and maybe an answer will materialize...That's not going to happen here!
For now, let's suspend judgment about why your truck and millions of other 4x4s are in this predicament. You've installed all of this hardware, and it's time to make the vehicle track as safely as possible—and for the tires to last.
As for front axle lateral alignment, your adjustable track bar is a real asset. Alignment does reference from the rear axle, and for good reason. The term "thrust" is just what it sounds like: The rear axle on a RWD vehicle is the traction point, pushing the frame and the entire vehicle forward from the rear. Unless you're driving backward, your rear-drive truck requires the front axle to align squarely under thrust. (Thus the term "thrust alignment"!) The axles must be square, in any case.
To illustrate, draw a line forward and perpendicular to the centerline of the rear axle. This follows the driveline in approximate terms—unless the driveline is offset like with a side-drive transfer case. This line of force, aimed forward and perpendicular to the rear axle, becomes the reference point for the front axle's position. The front axle ends up parallel to the rear axle, which is simple to visualize on beam axle trucks like our Ram 3500 models. The front axle must also align sideways or laterally, the reason for your adjustable track bar.
Whether the frame is perfectly square or not, if the front axle is parallel to the rear axle (plane view from the top), and if the axles center laterally with each other, you can align the truck's front end. The frame should be square, though, because an out-of-square frame would place the springs, suspension arms and steering linkage at odd angles with the axles.
So, let's start with a square frame, no collision damage, and a rear axle that sets squarely in the truck. It's much easier with our leaf sprung, beam rear axle: The centering points for the rear axle are simply the leaf spring center bolts and the axle's spring perch holes—plus any spacer block alignment holes or pins.
Rear axle in place, you can use the string-in-diamond method for setting the beam front axle's position for both parallel to the rear axle and laterally on center. I used the string method for two illustrated how-to articles at the magazine: my Jeep XJ Cherokee 6-inch long arm installation at the "Jeep XJ Cherokee & MJ Comanche 4WD Workshop" (see the left panel menu) and also the Jeep TJ Wrangler Rubicon Full-Traction Ultimate 4-inch lift. The XJ Cherokee is similar to our Dodge Ram trucks with link-and-coil front suspension and leaf springs at the rear. Both Jeep vehicles have beam axles front and rear.
Critical to a string-in-diamond beam axle alignment is finding precise reference points at each of the axles. You must have a reference point at each side of the front axle that is truly equal distance from the axle's centerline. The rear axle on our trucks is simple: Use the leaf spring center bolts as the rear reference points. On a Jeep TJ or JK Wrangler, there are matching suspension points that are equidistant from the rear axle's centerline.
The front axle should align with equal string lengths to the rear axle, measured in cross or "diamond". This means measuring from the front axle's left side reference point to the right rear spring center bolt, then from the front axle's right side reference point to the rear axle left side spring center bolt.
This measurement must be very accurate. Even 1/16"-1/8" variance can make a difference. If there are obstacles under the chassis that prevent an accurate measurement, you may need to relocate your reference points or even make "extensions" from the reference points to below the obstacles...For these measurements, you can have the axles suspended to full drop, which may help the string lines clear the transfer case skid plate, the exhaust or any other objects in the way.
Be creative. It's crucial that your four reference points reflect equal distances from the center of each beam axle outward to each axle's reference points. Strings then measure in cross between the front and rear axle reference points.
Again, the end game here is to have the axles parallel and tracking in line with each other. When the front axle is offset laterally, one way or the other, we call this "dog tracking".
Note: Don't be confused if one axle's track width is actually slightly wider than the other axle with the wheels in place. Some trucks (G.M. beam axle 4x4s come to mind) were designed this way, typically with the front axle slightly wider than the rear. I won't digress into "why" this was the design, simply know that if your reference points match side to side on each axle, and if you run the string lines in cross to matching points at the opposite axle, you will determine both the square and lateral alignment of the two axles.
Checking for square with two strings-in-cross is a simple function of geometry. If anyone is having difficulty understanding the principle, draw a perfect square on a piece of paper; now draw an "X" from opposite corners, intersecting at the middle. Measure the length of each "X" line. It will be equal. If you now use a rectangle instead of a square, the results will also be two equal length, intersecting lines. Play with this, and then transfer the "X" lines to your truck's chassis: On your long wheelbase Dodge Ram 3500 truck, the beam axles represent the short ends of a rectangle.
The most elaborate "4-wheel" alignment machine will not produce any more accurate results than doing a string line test properly. Once you get the axles square, you can concentrate on a front wheel alignment. This, as you say, is not rocket science, and it's even easier with a beam front axle.
Camber, in particular, is factory pre-set on a beam axle. Camber measurement indicates the degree to which the axle beams, steering knuckles and ball joints are in alignment. As you mention, you can make camber corrections with off-set ball joints, or eccentric ball-joint seats, and a source for such parts is Specialty Products Company.
Caution: I am against "bending" beam axles to correct slight camber issues unless a racing, weld-on truss is part of the straightening process. (Be aware, too, that welding on a truss is a good way to warp an axle and alter camber!) Consider the axle tube and center section materials plus the original stress that caused the axle to bend. There are metallurgical changes that take place with cold or hot bending. If you need to correct for a slightly bent or out-of-spec axle beam, use offset ball-joints or eccentric ball-joint seats. Make sure the bend did not stress-fracture the axle pieces. Toss out the axle housing if in doubt—you can transfer internal pieces and add-on goodies to a new housing. (See the magazine's many axle rebuilding articles and the HD videos on axle setup.)
Be aware that beam front axles come from the factory with +/- camber often slightly beyond the factory recommended camber degree range. I have seen this on Dana Jeep front axles, typically at the short beam side with more factory welding. An extra 1/8 to 1/4-degree camber at one side is not earthshattering and likely was acceptable during OEM axle assembly and installation. This will not impair vehicle handling and has negligible effect on tire wear if you rotate your tires on time. If you are adjusting caster and camber with offset ball-joints or eccentric ball-joint seats, bring both the caster and camber within their recommended degree ranges.
To answer your questions about "do-it-yourself" alignment, go no further than these three features that I've done at the magazine. They each get brisk traffic, addressing alignment goals with inexpensive solutions for doing your own alignment work.
First is the ‘DIY’ feature on a beam front axle wheel alignment. This is a useful article for understanding the principles of front wheel alignment as well as a 'how-to' on using an affordable SPC Off-Road Fastrax 91025 gauge kit designed for tires to 44" diameter. Click here to see this DIY how-to and equipment article.
For those on a shoestring budget, a single gauge kit will do. You can even improvise on the need for turn plates. SPC suggests using plastic sheeting beneath the front tires for a slip surface. On a beam axle, you can unload the weight slightly with the use of two floor jacks, raising the weighted axle evenly and just enough to take the heavy load off the front wheels and tires. This provides easier wheel turning.
There is also a photo closer to home, my Dodge Ram 3500 4x4 alignment after installing the Mopar lift kit. Here, I purchased inexpensive front turn plates ($100 for the pair!) from Gil Smith Racing at New York. Gil is a personable family guy, and these plates do the job despite the massive front end weight of the Cummins engine, 9.25" beam axle and 500 pounds of Warn bumper with M12000 winch and stainless wire.
For the Dodge Ram alignment, I added a second Fastrax 91025 alignment gauge kit from SPC to make toe setting easier and quicker. This way, you can use the winged braces and separate gauges at each side of the truck during the alignment procedure. This eliminates the need to swap a single gauge set from one side to the other.
Last, but surely not least, is the HD video walk-through of alignment on a Jeep TJ Wrangler Rubicon. You'll like this for both a visual orientation and added quips about the process. In this HD video, I do use the double alignment gauge sets from SPC and the Gil Smith turn plates. You’ll see how this speeds up the process.
Some additional pointers on doing your own alignment at this level: 1) make sure the floor is flat in both directions or compensate when taking the measurements with the bubble gauges, 2) make sure the turn plates are thin (like the Gil Smith type) or if you spring for more commercial type turn plates (available from several sources, do a Google search under "wheel alignment turn plates"), make sure you raise the rear of the truck to compensate for the turn plate height at the front. Even with a 140.5" or longer wheelbase, a sloping or leaning truck will throw off your camber and caster readings with the SPC 91025 bubble gauges...If you want to add a touch of professionalism, purchase a pair of rear slip plates from Gil Smith Racing that will enhance the work and raise the truck's back end to match the front turn plates.
As you mention, always save the toe-in setting for last. Camber and caster angle must be right, with the vehicle setting at static (curb) height on the ground, before setting toe. I use factory toe-in and caster angle settings, and the Dodge Ram handles very well. And, yes, caster is important, this and steering axis inclination (SAI) are what return the front wheels to center after coming out of a corner.
The surest sign of too little caster angle is a vehicle that requires turning the steering wheel back to center after a turn. I'm at 4-degrees positive caster on the Dodge Ram 3500, closer to 7-degees positive on the XJ Cherokee. More can sometimes be better for off-pavement turning radius; however, factory specs are the best for normal tire wear and handling in general.
I mentioned another specification that is of concern during alignment: steering axis inclination (SAI). We can go into this if you want, but the important thing to note for DIY alignment purposes is that strange caster and camber angle readings over the full turning arcs (illustrated in the XJ Cherokee alignment how-to article and shown in the TJ Wrangler HD video coverage) are an indication of a bent steering knuckle on a later beam axle 4x4 or a bent spindle on 2WD and vintage 4WD vehicles.
On alignment equipment that will identify SAI error, if all measurements are correct and SAI is off, we inspect the steering knuckle, spindle or unit bearing hub for damage. Make sure any strange readings are not from bad steering knuckle ball joints or worn wheel/hub bearings! Better yet, inspect for ball joint, wheel bearing and unit hub bearing wear before attempting the alignment. Check steering linkage for loose joints, too.
This is ground school, we can go from here. As a light- and medium-duty truck fleet mechanic in the late 'sixties, I began aligning my own beam axle Jeep CJ3A and vintage '55 Ford F100 at home. On these vehicles, toe-in could be set with nothing more than a tape measure. If you do wheel alignment with turn plates, the steering linkage and suspension will be unloaded, and the measurements will be that much more accurate. Add rear wheel slip plates and Fastrax gauges, and you can emulate a "pro" alignment!
Even on the vintage 2WD and 4WD fleet trucks with beam axles, I did quick, rough-in beam axle wheel alignments with nothing more than a tape measure or a portable, adjustable "toe bar". Floor jacks were placed evenly under the axle at each side. I would lift the axle beam just enough to "unload" the wheels and tires. Before setting toe, I made sure the wheel bearings and kingpin bushings or bearings were in good shape and adjusted properly.
Tape measure alignments on the trail are often necessary when someone bows a tie-rod on a tall rock or snaps a tie-rod in half. A Ready Welder tie-rod repair at Moab's Rose Garden is just one place where your tape measure alignment skills would be popular. This can get a vehicle home from the trail and tracking down the road safely to a wheel alignment shop. When using just a tape measure for toe-set, make sure you follow the tread pattern closely at the front and rear midline of the tires.
When using turn plates to unload and center up the steering linkage and suspension, it helps to bounce the front end. Push down on the front bumper a few times—the bumper is conveniently located at waist height on your Mega Cab!
If necessary, use a pair of floor jacks under the beam front axle to take weight off the wheels and tires, then lightly rock the steering wheel at its center position before setting the front tires and steering wheel to straight ahead. This will unload the steering linkage for more accurate alignment settings.
When using a tape measure only (not the Fastrax 91025's wing arms), always measure matching tread points. Measure as close to the midline (3 and 9 o'clock) of the tires as possible. Avoiding obstacles is sometimes difficult, but midline of the tires is preferred. Always set toe-in, followed by centering up the steering wheel. You center the steering wheel by adjusting the steering linkage sleeves—never by removing the steering wheel and repositioning it!
Caution: The steering wheel spokes are factory set to align with the center or “high” point of the steering gear in the straight ahead steering position. Bring the front wheels into alignment with the centered steering gear and steering wheel—not the other way around! If the steering wheel has been repositioned from factory, find the precise center point of the steering gear. Position the steering wheel there before aligning the front wheels to straight ahead. This also applies when making fine steering wheel position changes after an alignment: Adjust the steering linkage sleeves, do not reposition the steering wheel! Always check toe-in again when you center the steering wheel.
To illustrate how well you can do a 4-wheel alignment with strings, a tape measure, a common spirit level and a protractor, I installed the Full-Traction Ultimate lift kit on the Jeep TJ Wrangler Rubicon in just that way! The job began with the vehicle on my hoist and as level/parallel to the ground as possible.
I placed a pair of adjustable tripod stands beneath each axle and raised the vehicle straight up, just enough to install the lift kit. The axles remained on the stands with cables and other chassis attachments still in place.
After installing the kit, including a bevy of adjustable link arms and a unique rear tri-mount suspension system, I used the string method to square the axles. The rear axle location, fortunately, was fixed by the kit’s design, so this became the reference for making everything square with the frame. The approach was similar to the rear leaf springs and center bolts on our Dodge Ram 3500 trucks. In our case, the rear springs and axle spring perches locate the rear axle squarely at the frame.
I set the caster with a quality bubble level and a 180-degree, indexed protractor. I set toe-in with vehicle weight on the axles and tripod stands, using a tape measure fore and aft (as close to 3 and 9 o'clock as practical) at the front tire midlines, keeping the tape as level and parallel to the floor as possible. In my view, this was all just a preliminary, rough adjustment.
The next stop was a friend's shop with a $40K alignment rack capable of 4-wheel "thrust" alignment. On the alignment rack, to everyone's surprise, the entire suspension system took only one-half turn of one threaded link arm tube to be fully square! Caster was on, camber (non-adjustable on a solid beam axle) was okay, toe-in and centering of the steering wheel were just routine, slight adjustments.
Caster angle was within spec and did, as you describe, provide an acceptable angle for the front/pinion U-joint flange. With a double-Cardan (CV) joint at the transfer case, there is some leeway on this front axle pinion joint angle, and the compromise is between caster angle and U-joint angle. Like you comment, caster usually wins if you want the vehicle to steer correctly!
For modified trucks with suspension lifts and oversized wheels and tires, there are two very important considerations for handling. First, the aftermarket wheels' offset and the tire diameter must provide the right intersect point with the ground. This is the “scrub radius”.
Visualize the front wheels pointed straight ahead. Draw a line through the ball-joint stud centerlines and observe where that line intersects the tire tread at the ground. This point must be similar to the OEM wheel/tire intersection point, or you will swing the tire on an odd arc during turns, resulting in strange handling and premature tire wear. Scrub radius impacts tire wear as well as handling.
Secondly, consider the arc of radius and caster angle changes as the front suspension (link arms in your case) rise and set. Arc of radius is why we do long-arm kits for dramatic lift. When we increase suspension travel, short arms exaggerate the caster angle changes as the suspension extends and compresses.
Long link arms are the solution for increased suspension travel. Longer arms will create less caster angle change over the suspension and axle’s arc of travel—or radius. Simply put, you can set the caster at static/curb weighted chassis height, and the caster angle does not vary excessively as the link arms move up and down with the axle.
When buying an aftermarket suspension lift kit or bigger/wider wheels and tires, consider these issues. In looking at your Mega Cab components, I really like the stamina and quality of the aftermarket joints, link arms and drop brackets! What you want at the end of the day is suspension that behaves as well as or better than OEM engineering—yet with the lift and tires you desire. Going beyond “looks”, the goal is to understand the demands and dynamics of vehicle suspension and handling. Doing your own wheel alignment is a good start.
As for the rear axle, the usual concern is pinion and driveline angles for U-joint survival. Within reason, you can rotate the axle housing for pinion angle change without affecting vehicle handling, as the rear drive axle’s shafts are not sensitive to caster. (If we were talking about a front wheel drive car or an IRS/AWD car, there would likely be provision for adjusting rear wheel caster, camber and even toe-set.) For our trucks, tall lift blocks at the rear leaf springs can create some issues, mainly traction and spring windup related.
So, you might skip the visit to the local 4-wheel alignment shop and the brief Car and Driver read—likely just long enough for the tech to discover that specifications for your lifted and modified '06 Dodge Ram 4x4 Mega Cab are nowhere to be found in the alignment machine's software program. As an option, consider the SPC Off-Road 91025 alignment equipment...Two kits work even better than one!
Used properly, this accurate, portable SPC setup can help you dial your front end alignment for both safety and good tire life. Bubble caster and camber gauges were an automotive industry standard for at least sixty years prior to light beam, infrared, RF and laser alignment equipment.
I entered the service and repair industry when we were still called "mechanics", and breaker point ignitions were the norm. Smaller shops used floating caster/camber bubble gauges that fit magnetically to the end of front wheel hubs! Professionally, I've spun wrenches all the way into the contemporary electronic fuel-and-spark management "technician" era. Electronic, beam four-wheel alignment equipment has been in vogue for more than three decades now...I find it advantageous to have walked in both worlds.
Beyond alignment, make sure that the wheel offset and tire diameter add up to a safe and tolerable "scrub radius”. As an alternative to Car and Driver, sift through this Wiki info about scrub radius and SAI. When you widen the wheel rims, you can only go inward so far. (Rotors, calipers and hubs limit the inward wheel position.) For that reason, wide rims almost always offset to the "negative" direction or outward. If there are wheel backspacing choices, match up the wheel width, backspacing and tire diameter wisely! The concern here is the scrub radius.
We lift our vehicles and mount oversize wheels and tires for a variety of reasons. In the end, we get to make the handling and safety corrections that these modifications require. Routine tire rotation is always essential, even more so when scrub radius and arc of radius get compromised. Once you dial the front end alignment to the best point possible, watch for ball-joint wear, wheel bearing or hub bearing wear and any tire issues. This can sometimes be the price for a lift and oversized tires. We can, however, reduce, minimize or even eliminate that risk and expense!
Posted by Hendogg on 18 December 2014 - 12:00 PM
Posted by Moses Ludel on 13 November 2014 - 09:55 AM
Wow, very low mileage on this one, KeriOkie! For a Cummins Ram truck, this is a great find, barely broken-in! I looked at the pics. Other than color, you have essentially the same truck we bought new as an '05 model ten years ago.
If the truck is bone stock and you're after mileage, your "new" Ram 3500 is in the best form it will ever be. With the 48RE automatic and 3.73 axle gearing, if you run the engine between 1600 and 1900 rpm, you will gain maximum fuel efficiency. As others like Megatron note, don't do heavy throttle dead starts or hold the transmission in lower gears under high rpm sprints. Running empty, using mild throttle at this rpm range can yield 23-24 mpg if that's your aim.
I have recommended engine tune reprogramming for modified and weightier models that have already gone over the cliff with fuel efficiency losses. For stone stock gearing, stock tire size, no lift or colossal add-ons, Chrysler had this truck dialed for fuel efficiency in stock form. Yes, the Hypertech 'Max Energy' programmer bumps up horsepower and torque but at a higher rpm (2100 rpm torque peak instead of 1600). If you experiment with this approach, there is a high, mild and stock performance setting. Megatron talks about a programmer that has push-button settings, which would be handier than the software "reprogramming" necessary to change modes with the Hypertech setup.
Try driving the truck as-is and enjoy it for a bit before considering any modifications or changes. Assuming it has stock engine programming now, you're in business for power and fuel efficiency within the 1600-1900 rpm range. For fuel efficiency, the closer to 1600 rpm, the better! My very best mileage when stone stock without a load was 25 mpg, done over a 500-plus mile test (Reno, Nevada to Portland, Oregon) with varied road and load conditions, driving mostly between 1600-1800 rpm.
All of us need to keep in mind that extracting latent horsepower and torque from a turbo-diesel like the ISB Cummins comes at a price: heat and fuel consumption. If we boost horsepower or torque and stay in the throttle to realize these gains under severe loads, the result is engine-killing heat and huge losses in fuel efficiency. If you intend to push an ISB Cummins diesel, I heartily recommend a pyrometer, installed pre-turbo in the exhaust manifold (without leaving drill or tap debris in the manifold!) to monitor maximum exhaust manifold temperatures! Apply less right foot pressure to lower temperatures.
Keep us posted on this gem of a find!
Posted by Moses Ludel on 28 June 2013 - 05:26 PM
Thanks for catching this post...It's among my favorite subjects, as you might have guessed...
Once the axle gearing is correct, the other factors that drop fuel mileage on your '06 Ram 3500 Cummins would be 1) the increased vehicle height (kiss off aerodynamics of any kind!) and 2) the vehicle's weight over stock. I wound up in a similar situation with a 4" lift, 35" tires and a carload of "cool" accessories! Not sure of your accessories, I added approximately 1,350 pounds to my over-the-road, "unloaded" weight...kind of like perpetually pulling a well equipped tent trailer!
Hey, we all like the "look" and utility of a lifted and accessorized Ram 3500 4x4! Here, the truck we purchased new in October 2004 is undergoing a metamorphosis in 2011, getting ready for show time at the BFGoodrich Tires booth, Off-Road Expo at Pomona, CA! Let's see now, the lift, wheels and 35" tires, we'll add a utility fuel tank that takes us to Moab, Utah and back from the Reno, Nevada area...and that M12000 Warn winch will be a dandy when needed! Oops, there went the 25 mpg. Time for a 4.56:1 axle gear change out!
(Can't see the photos? Join our free forums and get the full benefits of membership!)
Most have no idea how quickly the upgrades and accessory weight add up: Try oversized American Eagle wheels and BFG tires for at least 150# over stock including the spare; a Mopar lift kit after swapping out OEM parts for an added 50 pounds; a Warn M12000 winch for 140# (bare winch wound with wire rope); front and rear HD bumpers for an extra 300#; a Transfer Flow cross bed fuel tank with additional fuel on board: 75 gallons @ 7.1 lb/gallon for Low Sulphur diesel = 532.5 pounds when full plus the aluminized steel tank's weight! Oh, and I do like the three Bestop Treksteps for 60 pounds plus.
I'll comment on your gearing projections, just did the math...If your tire's revolutions per mile are around 560 (Toyo rating for several popular 37" diameter tires, confirm your exact revs per mile), then here are your engine speeds at practical road speeds in overdrive (0.69:1):
4.88 gears @ 70 mph = 2200 engine rpm
4.88 gears @ 65 mph = 2043 engine rpm
4.88 gears @ 55 mph = 1728 engine rpm
4.56 gears @ 70 mph = 2056 engine rpm
4.56 gears @ 65 mph = 1909 engine rpm
4.56 gears @ 55 mph = 1615 engine rpm
According to Cummins, you should use the 4.88:1 gears for a truck under 10000# GVWR and intended for 70 mph cruise. In my experience, though, if fuel mileage were your sole aim without carrying cargo or trailer pulling, I would suggest the 4.56 gearing. This would keep you "in the window" for maximum fuel economy. However, even a light travel trailer would immediately tip the scale toward taxing the engine, which could impact both fuel efficiency and engine life—plus overload the transmission (clutch if manual) and driveline.
Actually, with your 37" tires, the 4.56:1 ratio would be much like your 3.73:1 gears with the Ram 3500's stock tire size. (That was also before accessory add-ons and the lift, too!) In overdrive, that off-the-showroom floor truck fell well below Cummins' recommended 2,150 rpm at 65 mph baseline for fuel efficiency and commercial hauling. I'd again emphasize that 23-25 mpg highway was readily achievable with the stock tires, 3.73 gearing and no load at 65-69 mph (approximately 1800-1950 rpm).
If you pull a trailer very seldom and your add-on accessories weight is modest, fuel efficiency would be good between 55 and 70 mph with 4.56:1 gearing and 37" tires. If the add-ons are like mine, however, your truck has a load before you stack on cargo! The 4.56:1 gearing would not be low enough, you'd be better off with the 4.88:1 gears.
Note: This is why I opted for 4.56:1 with the 35" tires, rather than fiddle with 4.10:1, which would have been the direct correction for the bigger tires. We plan to pull a trailer on occasion—without destroying the powertrain. Also, as I've shared, between the lift height and added accessories weight, this is not the stock truck any more.
Your decision comes down to load and intended cruising speed. Considering the height and weight of your Ram 3500 Mega Cab, you'd likely be "happier", performance wise, with 4.88 gears. When you want fuel efficiency, hold the speed to 65 mph. If that's too slow and you want to "cruise" at 70-plus mph yet get the best fuel efficiency for that rate of speed, consider 4.56:1 axle gearing. You can see by the calculations that the engine would be in Cummins' recommended zone of 2100-2400 rpm when cruising at 72 mph (2114 engine rpm) with 4.56:1 gears in overdrive. With 4.88:1 gears at 72 mph in overdrive, the engine would spin 2263 rpm and eat up fuel.
Cruise speeds above 65 mph will eat fuel, regardless...Moving as much mass as our trucks at speeds above 65 mph requires increasingly more fuel. Base your choice on what cruise speed you find acceptable on the highway—the faster you go, the more fuel the engine will use...guaranteed!
The acceleration might be marginally better with 4.88:1 gears. In terms of gear stamina with a given ring gear size (11.5" and 9.25" in our case), the 4.56 gears are actually stronger due to the larger pinion gear head size. (This is slightly offset by the 4.88:1 additional gear reduction, which helps reduce load a bit.) Given our Ram 3500 ring gear sizes, the stamina distinction is not as severe—nothing like sticking 4.88:1 gears in a Dana 35 Jeep rear axle with a 7.625" diameter ring gear!
We can kick this around more, Megatron. Cummins recommends spinning the engine for "efficiency" and, at least commercially, does not want to "lug" the engine below 1900 rpm at highway cruising speeds. Note that a truck under 10000# GVWR with an H.O. 5.9L Cummins ISB engine is less susceptible to lugging than a Cummins ISB engine in a medium-duty truck.
If you're running an aftermarket performance module or "chip", or have done any other tuning or engine modifications, we need to discuss those variables, too...That could change the rpm scale for maximum performance and fuel efficiency, in turn shifting the rpm band for the gearing.
Posted by elinamaria on 12 February 2014 - 02:37 AM
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Posted by forman on 04 February 2014 - 07:55 PM
Hey I enjoyed the compressor story!
Today I was able to start disassembling the transfer case I followed your procedure and took some photos.
The impact driver worked great on the yoke nuts and to be honest most of what I disassembled today was very easily done. I have to admit once I learned the new to me transfer case nomenclature it went very well, I'm having fun.
I noticed that the intermediate shaft had some wear, I could feel where the gears rode on the shaft. The gear teeth that I can see so far aren't showing any sign of wear I hope some of the photos will show.
In the first photo the bushing on the left looks rough on the outside.
Posted by Moses Ludel on 26 March 2015 - 04:18 PM
DJDRAGON...I like your assessment, you do need to determine whether this is reverse gear in the transmission or a the transfer case issue. If you need to rebuild the AX15, I'm getting excellent feedback on my step-by-step video how-to rental at Vimeo On Demand: www.vimeo.com/ondemand/ax15rebuild. Follow this link and watch the free trailer.
The reverse gear is hypersensitive and in close proximity to the rear of the case. On the other hand, the NP231 transfer case could have a clearance issue on the chain, planetary damage, shift cog damage, or simply damage to the fork slippers.
I'm pleased that you have the shop and resources to lift the vehicle and safely listen to the noise with a stethoscope. Please share whether the noise is at the rear of the transmission (actually at the front end of the extension adapter) or at the transfer case. It should be relatively easy to draw this distinction with a stethoscope. If at the transfer case, I'm targeting the NP231's shift slippers as a first possibility, there's apparently no noise beyond this symptom. Think in terms of backing off the throttle in reverse and the resulting TC shift hub movement caused by loose forks or shifter slippers.
Posted by JanetBrown on 06 March 2015 - 10:27 AM
Ok so I have now had a response from Customer Services as follows:
"We refer to our email of 19th November 2014 (copy of which is attached) in which we advised you that Fiat Group Automobiles UK Ltd is assisting with the coordination of aftercare of Jeep vehicles registered on or before 1st September 2010.Fiat Group Automobiles UK Ltd would like to assure you that have been doing all we can to expedite procurement of the tow bar which we have identified and which meets the requirements of the recall campaign.
By way of update, we would like to advise you that availability of the tow bar is anticipated for the end of April 2015. We will contact you again once we have final confirmation of UK delivery.
So end of April then........................
Posted by JanetBrown on 19 February 2015 - 10:35 AM
Below is the response to an email I sent earlier today, the email has not answered any of the many questions I have asked for the second time. However it does say that I will hear further by the end of next week - mind you not going to be holding my breath:
We have identified a source for a tow bar which is currently undergoing tests to ensure it complies with the requirements of the Recall Campaign. We hope to conclude the process as soon as possible and would like to assure you that we are doing everything we can to expedite this. We will contact you with further information as soon as this becomes available.
Please be assured that we will provide you with a further update on this matter by the end of next week.
Posted by Moses Ludel on 03 February 2015 - 06:08 PM
Looks like this tool should do the job, I thought it would be something of this nature...Loctite Sleeve Retainer works! It meets requirements for this application, too. Here are the product details:
This compound will secure, help seal and withstand the heat exposure in the application. You can remove the parts with pre-heating to break the bond. There are instructions for its use.
Posted by Moses Ludel on 30 January 2015 - 04:31 PM
That makes sense. The repair sleeve must be metal, not just a nylon lip guide...When you do find a snout repair sleeve (metal), let us know what special installation tool is needed to drive or press the sleeve onto the crankshaft snout without flaring the sleeve end or beating the crankshaft against its main thrust bearing! Maybe improvising a setup like the harmonic balancer installation tool would work?
It was helpful to have the Elf on the Shelf hold the Speedy Sleeve in the seal for this picture...He's doing a great job!
Posted by Moses Ludel on 30 January 2015 - 04:26 PM
Ah, the fixture attaches to the injector bolt holes, that makes more sense in terms of positioning. The piston crowns should have valve reliefs, so the valves are not digging their edges into the piston crowns. The force is minimal against the pistons, the tool is simply trying to compress the springs enough to enable dislodging the valve keepers. Cool!
Posted by Moses Ludel on 30 January 2015 - 04:18 PM
Wow, Megatron, significant gains with both stock and performance tunes! Where did the EGT go? Was this usable power, and how did it help your truck's drivability? Trailer pulling ability?
We'll have to arrange a get together for Elf on the Shelf and the Noid...
Posted by Moses Ludel on 29 January 2015 - 10:29 PM
Megatron, I began reading this topic with great interest, as I have the same turbo on my '05 5.9L Cummins...The concept is very interesting, and I promise that I'll read the content carefully. However, I began reviewing your photos, started laughing at the ways you enlisted the help of the winter guy, and couldn't read any further....
Years ago, 1990 to be precise, our youngest son came home from school with a Domino's Pizza Noid in hand. I took one look at the Noid and knew he'd make the perfect helper for technical photography. He wore a red outfit and had white gloved hands that could point out details underhood or on the benchtop, showing off mechanical subjects, just the perfect pointer outer guy for photo close-up projects! He could do things like your bright eyed helper and even stood on his head well—it was the long ears.
I was on a roll when the editor (happened to be Duane Elliott at Argus' OFF-ROAD Magazine) put the kibosh on the Noid. Duane was certain that if we published any of my technical photos with the Noid pointing out parts or demonstrating safe shop practices, Domino's would sue the magazine for trademark infringement. I thought this was nonsense. If anything, we might have gotten fined for violating Noid labor laws. I had the Noid tagging along on my feverish pitch assignments and hadn't considered the overtime involved. I took it for granted that he was supposed to buck up...
In fact, this seemed like incredible advertising for Domino's, but I had no choice and was forced to crop the photos and retire the Noid before his debut in the magazine...He's still atop my bookcase with his long rabbit-like ears, silly grin and, unfortunately, idle hands.
Will read your Wicked Wheel 2 details with earnest...as soon as I stop laughing at your helper in action...
Posted by Moses Ludel on 29 January 2015 - 01:36 PM
This is ingenious, Megatron! Compressing all four valve springs at one time, using the factory pedestal/fulcrum shaft mounting point as a base...fast, easy, failsafe with all four valves closed and the piston for that cylinder at TDC! This is a good one...What a time saver!
Looks like the valve keepers are well exposed, too, reducing risk (as you hinted earlier) of the valve keepers dropping through an engine opening and into the inner workings or the oil pan. Still a good idea to fill all exposed openings with clean rags when you do this job...
Posted by Moses Ludel on 27 January 2015 - 12:19 PM
This review and testimonial are very helpful, Megatron...I have the one-piece factory rear shaft with my 140.5" wheelbase Quad-Cab. This driveshaft has a massive damper at the slip yoke end (transfer case), which apparently does nothing to prevent vibration. Your OE shaft had this damper, too.
I replaced the first U-joint set myself at just under 95,000 miles, which is supposed to be a longevity record for these OEM drivelines. Frankly, I thought the permanently sealed joint failure was way premature for the conservative service this Ram 3500 4WD has seen. I replaced the OE joints with HD grease-fitting type Delco, they've held for 50K miles so far with periodic lubing—using my commercial grade hand grease gun.
Note: A grease fitting joint is always regarded as having less stamina than a permanently sealed joint. This is because the cross gets drilled for the lube fitting and passageway, weakening the cross section of the joint. I was assured that this replacement joint is Delco's "Heavy Duty" item, though I'm not convinced...On 4x4 front axle shaft steering joints or any high load joint, a permanently sealed cross-type joint is required. The only "exception" to this rule would be a cross joint with the grease fitting at an outer face of a bearing cap. One could speculate about the "weakening" of the bearing cap by the drilled and tapped grease fitting hole. Balance could also be affected, though the weight difference would be negligible: The grease fitting likely weights the same as the missing (drilled and tapped) bearing cap material.
Your driveline being a non-CV type with a single cross joint at each end, the length actually helps diminish the drop angle (side view). This is a good thing. If your front and rear joints have properly cancelling angles, this shaft should last a very long time. I see the U-joints are Spicer XL 1480 permanently greased and sealed type, incredibly strong and well suited for your performance upgrades.
So, I'm listening carefully here, as I would like to boot kick the OE driveline and weighty damper. The 4.56 axle gear change moved the subtle driveline vibration to a different road speed, and the vibration is driveline speed related. I distinctly believe this rear shaft is out of balance.
Posted by Moses Ludel on 23 January 2015 - 02:13 PM
You're welcome...Note that the Performance Diesel product is for the rear main seal. They may also have a product for the front snout/timing gear cover seal end. Again, I'd like to know if Cummins offers a front/timing gear seal kit. If Cummins offers this rear repair kit, maybe it has a front crank snout kit as well!
Posted by Moses Ludel on 22 January 2015 - 03:54 PM
Megatron, I read your post with great interest. As a career automotive/truck wrench, I'm familiar with sleeve repair kits for crankshaft snouts, and they are popular for Cummins engines or any engine with seals designed to last a long time, i.e., seals with greater lip pressure and made of a stronger (higher durometer) material. There are actually two "remedies" available, and the groove in the snout is not that unusual.
Solution One: A redesign seal specifically with an offset lip. Quality automotive seal manufacturers often do this as a matter of course, by designing a seal with either an offset lip or a double lip, sometimes making the outer (dust) seal lip more functional. In any case, this would be noted in the seal manufacturer's catalog or be obvious by comparison with the OEM seal. That's a quick solution because you're simply replacing the OE seal with this improved or modified aftermarket seal. One limitation would be a seal jacket depth that is too shallow and will not allow for a significant off-set of the sealing lip.
Solution Two: A crankshaft snout sleeve repair kit. This is a press-on or tap-on bushing/sleeve, always reasonably thin, that can be pressed or driven onto the crankshaft snout. Depending upon the application, the snout repair sleeve kit may allow installation with the engine in the chassis. Some sleeve kits are for the engine remanufacturing or machine shop industry and may require a press-on approach with the crankshaft removed from the engine...Knowing us, Megatron, we'd likely find an in-chassis way to press/pull the sleeve onto the snout. I'm thinking of something like a harmonic balancer installation tool with some improvised adapters.
Here are some quick links to products of interest:
1) Here's a National OEM replacement seal with a proprietary bore seal, a nice design that would not require sealant, maybe the type you installed? https://www.rockauto...4386&cc=1432342.
2) Timken's equivalent seal with a protective nylon installation sleeve, not to be mistaken for a snout repair, merely for installation without seal lip damage, the tool does not stay in place: https://www.rockauto...7397&cc=1432342
3) This seal comes with a "wear sleeve", though the device looks more like a spacer that repositions the seal lip and maybe adds a deflector or wiper seal? http://www.cumminspa...t.com/DS3802820
4) Rear main seal and crankshaft repair sleeve, a popular item though the wrong end of the crankshaft for what you want: http://www.perfdiese...hp?Product=1094
6) Here's a Speedi Sleeve kit advertised for the front crankshaft seal, perhaps what you seek: http://www.dieselstu...macrspsl59.html. Verify the quality before plunging.
Suggestion: Cummins may have its own crankshaft front sleeve and seal kit. I would check directly with Cummins before buying any product.
I fully agree that a front timing cover seal will be much easier to install with the cover off the engine. You can back up the seal seat in the cover and discover that the seal will actually drive into place without the cover absorbing each tap of the hammer. You can then use the nylon protective sleeve that comes with a quality seal to install the cover and seal over the crankshaft snout. Make sure the seal is compatible with the larger O.D. created by the repair sleeve.
Keep us posted on the solution you find!
Posted by Moses Ludel on 21 January 2015 - 09:51 PM
Megatron...Since the proper re-torque of rod bolts is essentially the same clamping force as the 5.9L engine's original torque setting, you likely did not distort the big-end bores of the connecting rods. Insert type bearings have a built-in "crush" design that makes the bearing round when the big-end bore is tightened and concentric. Simply installing new (better quality) bolts should not distort these rod big end bores. Over-torqueing rod or main bolts or nuts could create an issue, however, as the bearing saddles (mains) and rod big end bores can be distorted.
Rod cap alignment is crucial, but this is controlled by the rod design or the rod bolt/stud shank. Most connecting rod bolts have a near interference fit, intentionally designed to keep the cap from moving or migrating under load. Knurled or serrated bolt shanks create that "must have the cap perfectly square" during assembly feel. Cummins builds troughs and raised surfaces in its rod cap-to-rod shank interface. Unlike the common flat, parallel faces of most rod shanks and caps, the Cummins design helps hold these two pieces in alignment.
I like your take on ever so slight changes in the rod big-end or bearing shape. Yet there is always oil clearance on rod bearings. The Cummins 5.9L ISB is no exception. If you did "distort" the bearing during your work, that would likely be well within the 0.0001"-0.0005" range. You would still be floating the rod on a film of oil. Oil separation is what keeps these metal parts from making contact during normal operation. Normally, the oil pump supplies ample oil; the bearing clearance allows the oil film to prevent parts contact. This is why 95% of rod and main bearing wear over the lifespan of an engine is from initial engine startup, before these bearings have a pressurized charge of oil.
Note: This is also why I have always changed my own engine oil. I fill my vertically mounted oil filters, like the Cummins 5.9L, with fresh oil prior to installation. I cut the initial start and oil pickup time considerably.
I'll share some quick anecdotes...In the course of my automotive career, I've worked at and with automotive machine shops. This dates back to the late 'sixties. In 1997, we purchased a used 1987 Ford F150 SWB 4x4 pickup for our son's first ride. (At cowboy country, this was the machine.) Nice truck with the legendary 300 CID/4.9L inline six and an NP435 truck-type four speed transmission, 8.8" rear axle. First year for MPI, had the power steering option and an aftermarket sound system...The vehicle, though very clean and well kept, came with nebulous miles on it, and the engine had a very subtle cold morning start-up rattle (lower end) that got my attention.
I planned out a father/son rebuild, we removed and tore down the engine, then sublet the machine work to a local and reputable shop. The owner being a friend, we were on the same page about machining practices. After hot tanking and new cam bearings, every machining need was met, including full cylinder head work, rod machining and new piston fitting, re-boring, decking and reciprocal parts balancing. I went along with his recommendation to "polish" rather than regrind the crankshaft's journals. (Journals were remarkably true despite obvious, visible wear on the insert bearing shells.) The crankshaft was original with its standard size FoMoCo bearings. I thoroughly built the engine to my usual "blueprint" aims. The bearings furnished were high quality at standard journal size.
Turns out that Ford had a recognized problem with excessive oil/bearing clearance on these engines. In particular, there were warranty and shop repairs addressing 300 sixes with cold start knock even when new or near new. (In the 'nineties, GM had this problem with V-8 truck engines.) The problem was a common one: two much oil clearance on the rod-to-crankshaft journals. Well, it just so happens that I had the 1993 Ford factory workshop manual set on one of my library shelves, a book provided graciously by friends at Ford Motor Company while I was writing and illustrating the Ford F-Series Pickup Owner's Bible (Bentley Publishers). That book earned a Ford SVO part number.
In the factory shop manual is a section devoted to every detail of the 300 CI six, including a specific reference to how a crankshaft bearing knock could be remedied in the chassis—like a warranty repair. The solution was simple: 1) Plastigage/measure the existing oil clearance on a "standard" bearing crankshaft and bearing set, 2) "roll in" undersize bearing shells to compensate for the excessive clearance.
Now this would seem simple enough until one reads the fine print. There are two common undersizes for a standard U.S. journal size crankshaft: 0.001" and 0.002". Ford talks about trying each size with a Plastigage test. Ford also recommends splitting up 0.001" and 0.002" size bearing sets if necessary and placing the 0.002" bearing shell half at the top side of the crankshaft (in the rod shank) and a 0.001" bearing shell half in the bottom side rod cap. Visualize these two bearing halves crushed and "round" in the bolted together rod shank and rod cap. Yes, one shell, the 0.002" bearing half, has a smaller inside radius than the other!
So, why is this acceptable as a new truck warranty fix? Because the rod rides on an oil film, and the overall bearing clearance, verified by Plastigage, provides the necessary space between the bearing and rod journal. Does this work? Yes, indeed. After running the freshly built engine and hearing a lessened cold start rattle (thanks to the new standard size bearings versus worn standard size bearings—plus a new Melling high volume oil pump to assure lubrication), I dropped the oil pan in the chassis.
Ford had built "high side" clearance into the crank-to-rod bearings, compounded by polishing the crankshaft journals. Using Plastigage, 0.001" undersize bearings were still too much clearance, and 0.002" undersize would have been too little clearance. I did the 0.001" and 0.002" mix per journal and brought the clearance into specification. The ever so slight morning knock now disappeared completely. Oil pressure picked up a token amount, too.
Note: According to my seventeen-year-old son (at the time) who wanted to drive the truck after the engine rebuild, I was the only person who could hear the excess clearance rattle at start-up with the standard size rod bearings, though that's unlikely. Over two decades earlier, I had donated a percentage of my hearing to the I-80 by-pass of Winnemucca highway job, running heavy equipment alongside the tortuous, high pitch screaming of two-stroke Jimmy diesels and raucous Caterpillar 1693 engines.
If anyone is curious about this two-size bearing remedy and its use as a bona fide and official repair, see pages 03-00-21 and 03-00-22 of the 1993 Ford factory F150 through F250 and F-Super Duty powertrain manual. The factory "Desired" rod clearance is 0.0008"-0.0015". "Allowable" is 0.0007"-0.0024". Plastigage is the final say, and I achieved the equivalent of 0.001" oil clearance with the use of the split size bearing halves on a polished OE crankshaft. We sold the truck six years later and have been updated since. It's running flawlessly to this day.
My bearing clearance parable points to a singular conclusion: Despite the extreme loads on your rod bearings and the Cummins diesel's propensity for making massive torque under a high compression ratio, I'm betting that your changing rod bolts and torqueing them properly has not diminished this 5.9L engine's lifespan by 27 seconds.
Footnote: My first tutelage at automotive machine shop work was with a postwar trained machinist, George Zirkle, who knew the intricacies of Stovebolt Chevy sixes with hot poured rod bearings. These were connecting rods that had Babbitt material melted and "poured" into their big ends—no insert bearings. Shims between the rod cap and shank could be pulled out to remedy minor rod clearance issues if the crankshaft journals were still reasonable round. These engines also used oil troughs across the top of the oil pan with connecting rod cap scuppers to pick up oil for the rod. The system was affectionately known as "dip and splash" oiling, and these 1937-53 216 engines ran a maximum of 15 PSI oil pressure on the gauge...By contrast, I also had the pleasure of working with the period GMC "Jimmy" inline sixes. The 270 GMC six featured insert rod bearings and many other durability features that helped the Allies win WWII with the deuce-and-a-half trucks. 1939-59 228/248/270/302 Jimmy sixes, GMC/Pontiac V-8s from 1955-59, and even the GMC 305 and 351 V-6s of the 1960s were days when a GMC truck meant considerably more quality and engineering than a Chevrolet, especially the engines and the upgraded chassis and axles. Imagine what the WWII outcome would have been if instead of GMC 270 sixes, General Motors had supplied Bowtie trucks with the 216 Stovebolt and its dip-and-splash oiling?...While I know this old iron intimately, I actually came of motoring age during the Muscle Car era. Knee deep in muscle cars, Jeep, light trucks and 4x4s, I had worked for several years as a light/medium duty truck fleet mechanic before the machine shop stint with George Zirkle in 1970-71.