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Dodge Ram 3500 with 48RE Automatic Transmission Shudders on Take-Off


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With my '06 Dodge Ram 3500 4x4 and 48RE transmission (Cummins diesel power), I notice when pulling and away and accelerating from a dead stop, like a stop sign, I will get the slightest vibration in the transmission. I assume it to be the clutch plates on the torque converter but not sure if that is right. it only does it from a dead stop and only through a few 100 rpms. it acts like trying to take off with a heavy load on a standard transmission.

 

I compare this to a solid flywheel conversion we did on an older powerstroke ford. to save a few bucks, we ordered the solid flywheel and clutch kit that didn't have the springs in it (like factory). well that was about the worst thing you could have done to that truck when hauling a heavy load. that thing would buck no matter how you feathered the clutch peddle lol. that action is what my truck feels like taking off, just not as violent and very subtle. no matter the tranny temp or load on the hitch. never less and never more. Any ideas?

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You described your take-off shudder well.  For openers, this is not likely converter related, as the converter clutch is not active at this speed.  If it is the converter, this means the converter clutch is dragging, in which case the symptoms would get steadily worse and cook the converter.  If you do suspect the converter, I can share how to test it in the truck.

 

Some would jump to transmission issues like band adjustment or worn clutch packs, motor mount issues, with the Cummins especially, and surely this could contribute.  Likely you have done the band adjustment during service work, though.  There would also be a benefit to upgrading to the aluminum accumulator piston that I describe and install in my Sonnax survival upgrades.  See that article at: http://www.4wdmechanix.com/Survival-Upgrades-for-Jeep-and-Dodge-Ram-Automatic-Transmissions.html.  You'll see the accumulator piston change there, too.

 

I like your gut comparison to the Ford Powerstroke that lost its clutch and flywheel harmonic dampening with the solid flywheel and clutch install.  You may have a similar harmonic or actual binding issue with the shudder you describe.  This may come as a surprise, but I would look elsewhere for that load shudder when you get the truck moving: check the rear driveline/U-joint angles.  You have a 6-inch lift on the truck, and I'll share some pointers here.

 

Your Mega Cab wheelbase likely uses the two-piece driveshaft.  If so, the shaft from the transfer case to mid-shaft bearing is probably stock still.  Maybe you've dropped the mid-shaft bearing to reduce driveline angle at the rear piece.  In any case, the U-joint angles must "cancel each other", meaning that an angle at the transfer case should have the same cancellation angle at the other end. 

 

A common issue with taller lifts is to not have the joint angles cancel properly.  For example, there may be a straight shaft out of the transfer case and through the mid-shaft bearing.  If so, the angle of the second/rear driveline should have U-joint angles that cancel each other (complementary angles) on the second or rear shaft. 

 

Many think it's great to angle or rotate the rear axle pinion upward to reduce pinion joint angle.  That only works if the angle either 1) matches the angle complement at the other end of the shaft (which is impossible) or 2) the front end of the shaft uses a double-Cardan or CV type joint as seen in the photo below.  Also see this Jeep XJ Cherokee article at the magazine for a single piece driveline and 6-inch long arm lift:

 

As a final note, you have shared that you're still running 3.73 axle gearing with the 37" oversized tires.  This is enough to cause extreme take-off loads and maybe even the shudder you describe.  The 3.73:1 gearing is marginal even with the factory tire diameters of less than 32".  At your current ratios, the gearing is way out of balance.

 

Moses

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  • 2 weeks later...

Thanks for the info, Moses!

 

  You are correct. During the last round of transmission updates we did spec as many things as we could during the build. Since the problem was there before and after, I ruled out some things like band adjustments and the accumulator. My inexperience with the diesel and its automatic transmission configuration is what lead me to suspect the transmission as the origin of the vibration. Call it fear that the 48re has problems lol.

 

  Okay. I took some time this weekend to explore my driveshaft angles and condition. Even though my truck is lifted, it has a matching carrier bearing drop bracket and the wedges for the rear leaf springs to correct rear end housing rotation. Everything looks to be close to correct (without using an accurate degree finder that is. (I have a new gauge on the way). All u-joints feel tight and the carrier bearing and bushing seem solid. However, there does seem to be and excessive amount of play on the pinion shaft going into the rear end. I am researching that currently (looking at your write up on rebuilding the AAM 11.5) so I can get an accurate measurement on play. This is one problem with not owning your truck from day one. You never really know what the last guy did with it.

 

   I have dealt with drive line angle issues in the past (lifted YJ) and I am aware of the need to be accurate with CV's and pinion angles. I spent countless hours testing different angles and joint types trying to overcome way too much lift with a short wheelbase ha-ha. What? Who hasn't wanted a 6" spring lift on top of a spring over kit?? I guess experience isn't learned from success but from failures instead.

 

  I am planning new gears later this summer to match my tire size. So even if I find that my rear is currently out of spec, I doubt I will take much action until it is time to swap them out. So if the problem truly lies within the rear it will be a while before I can confirm it.  

 

   When I get my new degree finder I will make a detailed account of driveline angles. Its hard to spot little variations with an analog style degree finder.  

 

  As always thanks for your replies and input. You should really write a book or two about mechanic work or even a magazine ;)

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We each have read or heard enough about the 48RE failures and aftermarket heavy duty replacement parts solutions to be skeptical. Worse yet for me, I tried to discuss the 48RE with a Mopar engineer at Moab.  We were test driving new Ram Power Wagons with the 5/6 speed automatics on Poison Spider Mesa Trail, and I could see his eyes glaze over.  This was a look I've seen many times as a professional, when manufacturers move on from a product and no longer have an interest in talking about "old technology".  He may have thought I was a 2005 Dodge Ram 3500 4x4 collector.  After all, the truck was six model years old!

 

Chrysler's now on to better things, including abandonment of the time-honored A727 transmission architecture with an overdrive thrown into the mix.  I remind myself that we saw the A727 Torqueflite behind 426 hemis in muscle cars, tucked into Class A motorhomes behind the 413 and 440 wedge-head V-8s, and joined to the original 12-valve Cummins in the earliest Cummins-Dodge Ram trucks.  Does the planetary overdrive really make that much difference?  Well, I do have suspicions about plastic accumulator pistons ("weight saving?") and stamped sheet metal looking band struts.

 

The driveline issues are a possibility, the angle gauge will eliminate guesswork.  You should be an expert after dealing with drivelines in a 94-inch wheelbase YJ Wrangler with a spring-over lift plus 6-inch spring lift!  For the record, the steeper a driveline angle (side view) and U-joint angles, the less torque the driveline can handle.  These physics reflect the angle of the U-joints and the torque needed to rotate them on a tilt.  Minimizing and matching driveline angles increases the life of U-joints and the torque capacity of the driveline.  1-1/2 to 2-degrees angle would be the least.  Less than that will not keep the needle bearings rotating.

 

Check out my 11.5" AAM axle rebuild and setup of the 4.56:1 ring and pinion gear set.  You'll find that the ring gear backlash setting is quite close for an axle/ring gear this large.  I did follow that setting with success.  The OEM 3.73 gears (bought the truck new) did have noticeable backlash like you describe.  That is gone now, the pinion backlash feels normal, and there is no "clunk" on forward to reverse gear changes.  It's rather annoying for an axle to have pinion clunk, though it's not necessarily a defect—especially on larger ring-and-pinion gear sets.

 

When you check that rotational play at the driveline, make sure you're not adding the differential gear play into the mix.  Move the shaft lightly to the points of first resistance.  That's the actual pinion shaft backlash.  If you're not hearing a whine on acceleration or coast, there's not likely a wear issue.  Check the axial/side movement of the pinion shaft, too.  As a point of interest, the 11.5" AAM axle is very stout, a proven G.M. design.

 

When you do swap gear sets, you can address the backlash issue.  Inspect the differential gears for play, too.  That's the time to make remedy.  As a footnote, changing the ring-and-pinion gear ratios will take a huge load off your 48RE.  The take-off shudder may diminish or disappear, an indication of torque converter loads.  You now have me paying attention to my truck's take-offs, and there is a moment of torque pull.  This could be the torque converter, it's high on the list of 48RE OEM parts "ready to go at any time"...

 

Write books?  You know what they say, "You're only as good as your last book—or next success!"  I say, after seven books that include best sellers, "Why not quit while you're ahead?"

 

Moses

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  • 8 months later...

Well I know its been a while since I kicked up this thread but I would like to post my findings and results.

 

   I took Moses advice and checked the angle of my rear drive shaft through the mid support with a digital level (after my eyes tried to tell me it looked fine lol). I discovered the angles where not as true as my eyes had lead me to believe. The front half of the shaft was at a different angle than the rear half.  So after a few measurements, some shims and two longer bolts... boom no more shudder on take off. I wouldn't have believed a set of 3/8" shims would make a difference but man did it ever. Truck takes off like factory again. Just proof that with an hour of time and some hand tools you can fix something with noticeable results lol.

 

  I guess to look back at it, these trucks make a considerable amount of power/torque and have to get a crazy amount of weight moving at take off. So something like a degree or so of angle can be magnified into a bigger problem. It is also a relief not always thinking that maybe your ring and pinion gear is on the fritz.

 

Thanks again, Moses, for taking time to help those who don't know become those who do know...

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Great, Megatron!  Your truck deserves to be free of shudders...

 

When the U-joint angles are different, opposing joint rotational forces work against each other.  Envision the angled arc that each U-joint follows as it rotates.  Since part of the joint "compresses" and the opposite side "expands" during each rotation, there is actually a speed-up and slow down over the arcs.  The driveshaft/joint input and output speeds remain the same; the U-joint design compensates for speed variations during each rotation of the joint.

 

Simply put, if the rear driveshaft's front U-joint angle differs from the rear U-joint angle, even if the two joints align properly in "phase", they have irregular speed-up/slow down patterns over their arcs of travel.  So you get a vibration because the shaft is fighting itself end to end.  Another cause for this vibration is when a splined driveshaft is assembled with the cross-joints misaligned.  This is "out of phase" and a real cause of vibration.  It can even tear apart the driveshaft since the speed-up and slow down over the U-joint arcs of travel run at different cycles.

 

You mention power/torque, and that brings up another concern.  A driveshaft loses torque capacity as the angle/slope of the shaft increases.  When a vehicle gets "lifted", the typical 4x4 scenario, if the driveshaft slope increases, the torque capacity of that driveshaft diminishes.  U-joint life suffers, and failure of joints is often common.  Even when the U-joint angles match as they should (by shimming the pinion angle or mid-shaft bearing properly), the U-joint lifespan is shortened.  This is strictly a function of U-joints: steeper angles make the joint weaker.

 

One way many offset this risk is the use of a CV or double-Cardan joint at the transfer case output yoke and a single Cardan joint at the rear axle pinion yoke.  The CV not only reduces the angle on each joint within the CV assembly, it also helps knock off the driveline slope factor considerably.  Since the double-Cardan CV joint has "self-cancelling" angles between the two cross joints, the rear axle joint angle (a single Cardan cross joint) can be very close to straight when measured at static vehicle height—with axles weighted or on the ground.

 

Actually, 0-degrees of U-joint angle is unacceptable for U-joint survival.  When running a CV driveshaft, I set the rear axle pinion joint (single-Cardan) for 1.5- to 2-degrees angle with the vehicle at static curb height and weighted.  This minor angle allows the joint's needle bearings to rotate in the bearing caps, which prevents them from starving for lube and also distributes the load uniformly over the needle bearing sets within the U-joint caps.

 

Note: The 1.5- to 2.0 degree rear joint angle is achieved by rotating the axle housing to angle the pinion shaft and yoke upward.  There is only one "downside" to doing this:  Lubrication/fill of the differential is thwarted by the dropped fill plug height.  Aftermarket differential covers for lifted trucks often have a relocated fill plug, higher on the cover to permit normal fill levels with the pinion angle rotated. 

 

The amount of rear axle rotation has little affect on chassis geometry or spring action.  Many lift kits provide a tilting spacer block to restore U-joint angles.  On installations that require use of spring-to-perch wedges to restore the rear U-joint angle, I use steel and not aluminum wedges.  Steel will withstand more punishment and not pound out or loosen over time.

 

Thanks for letting us know how this worked out, Megatron!  Great to hear your Ram is back in top form...

 

Moses

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  • 7 months later...

Well I know this is an old post but I'm going to bring it back to life ha-ha.

 

 Well after 6 months of no vibrations I started to get one at highways speeds. After playing around with some shims I finally decided it was the drive shaft itself causing the problems. I think running it out of alignment to long has lead to its inevitable failure. So in light of this I ordered a new aluminum 5" diameter one piece driveshaft. So over the next couple of days I will get it put in and tested out. Came with a no vibrations guarantee lol.

 

 I also made the switch to the larger U-Joints that are found in the manual version of our trucks. Or so I'm told. 1480 versus the 1410. What's a little more strength?? 100$ that's what lol.

 

 I will post pictures and findings.

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Megatron...Very curious how the aluminum driveshaft does.  I have an OEM driveline vibration, too, and would like to lighten up the driveshaft while remedying the problem.  Who makes the alloy driveshaft?  Off the shelf or custom built?

 

Also curious whether you're changing out the rear axle pinion flange to accommodate the 1480 joint.  There's a crush sleeve on the 11.5" AAM pinion shaft.  If you change the flange, use care to secure the flange without altering the crush sleeve's thickness.  The crush establishes the pinion bearing pre-load. 

 

Let me know if you have to change the pinion flange.  I'll provide some insight around installing a new flange without lousing up the preload on the pinion bearings—and at the same time, making sure that the pinion nut (install a new one, they are self-locking type) is secure.  This can be done!

 

Moses

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  • 2 months later...

Well I figured I would end this post with my last review on the new one piece drive shaft.

 

  I have been able to put just over 1000 miles on the new setup without any vibrations at any rpm/mph range. I'm 100% satisfied with the new setup.

 

post-33-0-87601800-1422374448_thumb.jpg

 

Here is a side by side with the old one.(Hopefully that picture loaded lol). I know time will tell like all things but the way I see it, my truck has 8" of lift with way more driveline angles than most people will ever see. I have a lot more power than the average truck with just a tuner will see. My truck is the Mega Cab so driveshaft length is longer than most trucks on the street. All this considered, I went from bad vibrations to no vibrations. If this setup works good for my application, it should work great for anyone with less of a setup.

 

  As for quality, its great. I had this shaft within 5 business days of ordering. There are some things that need to be done on your part prior to placing the order, but nothing you shouldn't expect when getting a new driveshaft. Install is really easy. I suggest putting a new seal on the output shaft of the transfer case when doing it. Mine was pretty brittle so out with the old and in with the new.

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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. 

 

Thanks!

 

Moses  

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  • 4 months later...

I installed this same drive shaft.  2006 Dodge Ram 2500 Cummins 5.9 and 48RE transmission.  Removed two piece and installed Drive Shaft Specialists' one piece aluminum with 1480 Spicer u-joints.

 

No vibration, however, there is a bearing growl noise that occurs when power applied and one of the following...shift from 2nd to third, third to fourth or fourth when torqure converter locks...generally this happens around 1,400 - 1,800 rpms (I don't think the RPMs has much to do with the noise, but more the power applied putting pressure on a bearing somewhere.)

 

Drive shaft was installed and then I noticed the noise.  Since then I've replaced the pinion bearings with proper pre-load, also replaced ring and pinion in rear.  New TrueTrack differential.  Mechanics say it's not any bearings after the drive shaft....  They say the large 5 inch diameter drive shaft will act like a megaphone and enhance any noise, but they say no bearing issues in the rear...

 

I called Drive Shaft Specialists and they confirmed that the large drive shaft will act like a megaphone, and most likely there is a bearing issue some where.

 

Transmission was rebuilt about 12,000 miles ago.  I guess the next step is to work with the transmission shop to see if a bearing is bad in the transmission???  No metal in the trans fluid???  Not sure what to look at next...what do you think?  Could this be a noise within the torque converter (two layer billet converter)???

 

Note, I do have a Yukon Free Wheel hub installed, so front differential does not spin when in 2wd. 

 

Thanks,

Dave

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Dave, welcome to the forums!  I would guess that Megatron will jump into your questions.

 

I would make a quick check of the slip yoke (transfer case end) lateral movement.  The transfer case output bearing or the slip yoke bushing could be worn or running out. 

 

Clarify whether the shaft vibrates when it changes speeds rapidly like deceleration then a light tip-in of throttle.  Back out, tip in.  I get a vibe here when doing this at speed that I'm certain is driveline imbalance triggered and amplified by a quick speed change.  The vibe seems to be on axle "coast".  I set the axle up as closely as practical (factory guidelines) on ring-and-pinion backlash.  Bearing preloads and backlash are right on spec, there is no sign of too much "play" anywhere, no axle noise, backlash clunk or bearing sounds.

 

Also, I strongly encourage checking the U-joint angles with the truck parked on level ground with typical curb load.  Angles should cancel, and if they don't you have a ripe candidate for vibration and stress.

 

If you guys like the Drive Shaft Specialists products, I'll open a dialogue with them...

 

Moses

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Hey Dave,

 

  Just to be clear, you never heard this noise before installing the new shaft correct? I don't totally buy off on the megaphone theory because the ends aren't open so no way for sound to be amplified. Can they resonate? Possibly I guess. Do you have a lift on your truck or any power adders that could have caused early wear on any parts? To me there would only be two bearings that could cause noise through the driveshaft. Pinion (which you changed) and the tail shaft output bearing in the T-case.

 

  You said the transmission was rebuilt but what about the T-case itself? Is it possible this bearing is going out? What mileage is on your truck? I have the same lock out conversion on my truck but I have often wondered if it would effect the oiling ability of the T-case since you are no longer turning the chain over, but I believe the internal oil pump should work.. I hope lol.

 

 If the noise doesn't consistently increase with speed then perhaps something in the transmission is afoul. Hate for it to be that because I know that's a pain to deal with. Who built your transmission?

 

 To be honest noises are the hardest to diagnose over the internet. They way you interpret sound and origin may be different than me. I would confirm that the new shaft wasn't to long during install and perhaps damaged the bearing in the T-case when compressing your suspension. Trust me its way cheaper and easier to work on the T-case than that transmission again lol. I mean if the rear is new, driveshaft is new, transmission fairly new and T-case is old.. well I would start there because either way its due for some service haha.

 

Dustin

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Thanks for your replies, Moses and Dustin.

 

Truck is not lifted.  Around 185,000 miles.  I do have an Edge Juice with Attitude.  However, I am very easy on the truck.  I generally have it on level 3-Drive.  I have a truck camper and when it's on the back of the truck I set the level to 2-Tow.  Again, am very gentle with the truck...never push the pedal hard or go wide open throttle.

 

I started to pay close attention to vibrations/sounds when I installed the new driveshaft around 1,500 miles ago.  That's the first time I heard the noise, but, it is possible the noise was there before.

 

I have the old driveshaft and am going to swap out to see if the noise is still there and/or as loud.

 

I also ordered a wireless Steelman ChassisEAR http://www.steelmantools.com/wireless-chassisear.html .  I'll put the clips/sensors on the differential near the pinion bearing, on the transfer case output shaft close to the bearing, etc,...to see if I can determine where the sound is coming from.

 

I do lock the hubs for a few miles once a month or so just to be sure front u-joints, differential and transfer case stay lubed, etc....

 

I'll let you know what I find out next week when I use the ChassisEAR.

 

Thanks,

Dave

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I attached a ChassisEAR sensor to a number of places this evening.  I think I have determined the problem.  No noise on the differential, a little noise on the transfer case near the drive shaft, a ton of noise towards the middle of the transfer case.  I'm pretty sure I can hear a stretched out chain in the transfer case slapping around...and most definitely slapping around at the same time that I can hear the noise that I described earlier.

 

Tomorrow I'll bring to the mechanic and have them take apart the transfer case...probably a rebuild is in order anyway with 185,000 miles...

 

Thanks for your help.

 

Dave

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Great diagnostic job, Dave!!!  Pleased that you took it to this level.  I have similar tools and strongly believe in pinpointing issues like this one.  No need to swap drivelines to experiment with the problem. 

 

Keep us posted on the TC findings and whether the chain was very loose...and if there's any sign of case damage, too.

 

Moses

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Dave,

 

  Glad you have narrowed down a good starting point for your issue. Let us know how it goes.

 

   Also, if you have time, could you maybe do a review post about that tool in one of the other forums? I have been on the fence about getting one but never met anyone that has used it. I have seen them used on TV a few times, but when the product pays for the review, well sometimes those reviews can be a little to much in favor of the product haha.

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Megatron...Thought I'd throw some details into the discussion.  My Steelman ChassisEAR kit has been a prized possession among my tools for well over a decade. I do not use it often, as you can see from the photo, but when one needs it, the tool is very valuable for multi-channel sound troubleshooting. It can be used with clips on various components or with a metal direct probe pickup. The multi-channels allow comparing noise levels at different locations, which helps distinguish noise sources and allows for decibel level comparisons.

 

post-1-0-87989700-1435075944_thumb.jpg
 

Unlike a stethoscope, ChassisEAR does not pick up transmitted or migrating noise, and you can set the sensitivity closely to narrow down the source. For valvetrain or our Cummins engine noise outputs, sensitivity settings must be very low, or the channels will override each other.

 

With long cords on the clips, you can drive down the road and listen to chassis, wheel/brake and driveline noises.  This is what Dave is doing.

Dave likely has details to add from his experience with the Steelman ChassisEAR.  It certainly has its place among professional diagnostics tools and is popular as an OE service department troubleshooting device for warranty work.

Moses

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