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Jeep CJ: Dana 60 High Pinion Axle Swap?


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So a friend of mine bought a project that someone has taken a front Dana60 and has it professionally made into the correct width to bolt in my cj7 wide track in the rear. What disadvantages or problem might I run into.

High would help drive shaft angle a bunch.Your thoughts? Thanks jim

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Two quick concerns, jrahman:  1)  the Dana 60 diff housing hangs very low, you'd need 37" or greater diameter tires to provide reasonable trail clearance at the axle housing center, and 2) this is a lot of unsprung axle weight, which requires springs and shock damping to offset it.

 

Many think they need this kind of axle.  Your horsepower can easily be handled by an AMC Model 20 rear axle with one-piece axle shaft conversion.  The Hummer (military IRS) uses a similar AMC center section!  Of course, the Hummer also uses a pair of portal reduction units and very tall, i.e. big pinion tooth count, ring-and-pinion gear sets.  AMC used the Model 20 in J-trucks with V-8s.  Better yet, the axle has only half the 2WD load when you're in 4WD, and the CJ weights a ton less than a loaded J-truck.  Power splits 50/50 through the Dana 300 transfer case.

 

I'm a fan of the AMC Model 20.  It has a larger ring gear than a Dana 44.  The only "weak link" in the AMC 20 is the axle shaft-to-wheel hub concoction, remedied with an aftermarket 1-piece axle shaft upgrade.  (Set up properly, the two-piece OE axle shafts and hubs can work well to 33" tires.)  The AMC 20 is actually easier to set up than a Dana 44, and you already have an AMC 20!

 

My thoughts, anyway...

 

Moses

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I prefer a manual locker and have used ARB Air Locker for decades.  This provides control on off-camber highways when you do not want to use a locker.  Automatic lockers are notorious for spinning short wheelbase vehicles around on icy or slick roads.  On off-camber icy highways, the vehicle's back end will drop to the low side of the road when an automatic locker compensates for wheel spin by spinning both rear wheels at the same time.  With a manual locker, I run open differential/unlocked mode under these driving conditions. 

 

There are other manual lockers, too.  My preference is full control over the use of the locker and an ability to unlock when useful or practical. 

 

Even a rear-only manual locker can be very beneficial.  Start there!  You can always add a front manual locker later if desired.

 

Moses

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  • 1 month later...

So it has been awhile but I bought a Moser engineering ford 9". I will be ordering a center section. a nodular with arb as you suggested. My new question is drive shaft related. Do I order my center with 1330 or 1350 yoke? And what to I do to my Dana 300 as it has a 1310 yoke? I would like to go to stronger than 1310 and have CV at case. Thoughts?

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jrahman...Check with Advance Adapters on a 1350 yoke output for the Dana 300, they may have a solution to provide 1350 at each end of the rear driveshaft.  Otherwise, 1310 and 1330 would be ample for a Jeep CJ with 33" tires! 

 

Just concentrate on heavy duty U-joints if you settle for the 1310 and 1330 combination.  Make sure the U-joint angles (TC output and rear axle pinion) cancel each other accurately with the vehicle at static/curb height and normal weight.  U-joint angle has more impact on stamina and U-joint life than any other factor.  U-joint slope will not be excessive with a 4" lift (presumed) and 33" tires.  Driveshaft slope angle determines the torque rating of the shaft.  Less slope, more torque capacity.

 

If driveshaft slope and joint angles are in question, a double-Cardan CV at the TC case end and rotating the rear axle pinion to a 1.5 to 2.0 degree U-joint angle at static, weighted curb height would be a solution...The CV joint will self-cancel angles.  The rear pinion flange U-joint needs this slight angle to keep the bearings rotating in the caps.

 

Moses

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