YJ Drive Shaft/ U-Joints

[jeep321]

Just a stock YJ, but why were the front u-joints on the rear drive shaft loose in the yoke (slid back and forth) ? And how does the front of the rear drive shaft bend enough (or something) to put yoke marks on the opposite shaft, and have the yoke peaned over (distorted) at the bearing caps? thanks

 

[Robert_Stephens]

Your rear drive shaft needs to be rebuilt with new splines, sleeve yoke and U- joints, front and rear and better, to save trouble later, get a new DL for the rear with the TC end with a CV joint. Will then last you about 5 times longer, smoother ride, and if you keep it greased it will serve you well, trouble free for a very long time.

Robert

 

[jfrabat]

Your rear drive shaft needs to be rebuilt with new splines, sleeve yoke and U- joints, front and rear and better, to save trouble later, get a new DL for the rear with the TC end with a CV joint. Will then last you about 5 times longer, smoother ride, and if you keep it greased it will serve you well, trouble free for a very long time.

Robert

If you DO decide to go for a CV shaft, remember you need to take the perches off the rear axle to correct the angle; otherwise, you will get STRONG vibrations at highway speeds... If you are looking for the simple answer, and you cannot get the perches welded on, it may not be worth the trouble (especially since you mention you are stick, I would not do a CV shaft myself).

 

[Robert_Stephens]

If you DO decide to go for a CV shaft, remember you need to take the perches off the rear axle to correct the angle; otherwise, you will get STRONG vibrations at highway speeds... If you are looking for the simple answer, and you cannot get the perches welded on, it may not be worth the trouble (especially since you mention you are stick, I would not do a CV shaft myself).

You are correct. I was suggesting to the OP. On my CJ, VEX, I went with 1 ton DLs from a F-350, CVs at each end at the Transfercase, 4:1 in the TC, T-18 military trans. with the 7.71 first gear low, and Dana 60s front and rear. That was the end of trouble, no matter where I am driving on the highway at 75 or in the wilds of the Desert Commons and elsewhere on the Earth. At 3 tons, VEX rides very very smooth as well.

If I were the OP, I'd do it like I did--bullet proof all the way, but it is his first Jeep so, go slow probably.

(I am using my Dana 30 for now and AMC 20 w/ Premier solid axles in rear, as my 60s are being refurbed at the 550,000 mile mark)

Thank you,

Robert

 

[Ggg]

He can add tapered shims to adjust pinion angle a little too.

 

[jfrabat]

He can add tapered shims to adjust pinion angle a little too.

I would advise against that; those are typically aluminum, and the crack (mine did). Also, most of the time you will not get them in sufficient increments to kiill the vibrations (the ones I got, which are the commonly available ones were about 2* to small).

 

[jeep321]

If you DO decide to go for a CV shaft, remember you need to take the perches off the rear axle to correct the angle; otherwise, you will get STRONG vibrations at highway speeds... If you are looking for the simple answer, and you cannot get the perches welded on, it may not be worth the trouble (especially since you mention you are stick, I would not do a CV shaft myself).

Thanks for the information. I put in a new splined yoke and two u-joints. Although this is my tenth Jeep (including a CJ, 2 YJ's, and a TJ) this is the first time I have had this problem and did not know if it was normal.

 

[jakec]

im not a fan of cv shafts either. changing u joints in those things sucks.

 

[Ggg]

I would advise against that; those are typically aluminum, and the crack (mine did). Also, most of the time you will not get them in sufficient increments to kiill the vibrations (the ones I got, which are the commonly available ones were about 2* to small).

I was talking about steel shims, although the only time I have seen the aluminum shims crack was when the shim was longer than the spring pad and hung over. Then the unsupported portion cracked but left the part that was supported by the spring pad still intact between the springs and spring pad. Installing the shims and going for a test drive to see if that solves a driveline vibration is a simple, cheap, quick way to definitively diagnose a possible cause. The small angle increments of the shims works perfect in this case because the OP has a stock YJ so any angle adjustment will be minimal.
As far as CV shafts go, if you had issues where there is contact being made in a regular u joint then you have three solutions. 1. limit axle travel so the joint no longer makes contact with itself. 2. grind some clearance into the joint. 3. install a SYE with a CV shaft because CV shafts will flex more than a u joint will.
Sounds like a previous owner did some off roading and really flexed the axles good.

 

[Robert_Stephens]

Totally correct on all points. On VEX with the Ford F-350 DLs front and rear, they have the steel sleeving and this latest set of joints in front and rear has lasted 550,000 miles now and are still firm, grease is clear, and no bad wear. I am pleased with this.

Your input is sound for his YJ. Good response.

Robert