Having some issues with the u-joint between the driveshaft and rear end on my son's RS. We put the rear end and aluminum drive shaft out of an '88 Formula under it awhile back. The u joint got a little loose on him the other day and started making a noise, he checked and said one of the caps had started to "move" outward so he pushed it back in and retightened the bolts. A few days later the driver shaft dropped off the yoke and pretty well did in the drive shaft.

I had noticed a few years back when I replaced my u joints that my IROC's yoke did not have those little "nubs" (I call them) in the yoke to both center and keep the caps from moving while locking the bolts down. I just centered mine up by feel and tightened them down and have not had a problem since.

My son ordered a cap kit from Jeg's that has caps designed to keep the bearing caps from moving so that should take care of it on his car.

I talked to my next door neighbor and he told me the u joints should be made for an snap ring that fits inside the half moon of the yoke and the half moon of the cap and then he showed me and old one he had. The ones we've bought for my IROC and my son's RS did not have these grooves in the bearing caps.

Now I wonder if the auto parts stores are selling us the wrong u joints. Any experience with this issue by others here?

Thanks.

 

I sold enough alum shafts at one point to believe that the 88 up shaft would not fit pre-88's without a different U. You might do a search on my name for the proper part number (or at least the one I used successfully).

JamesC

 

Aluminum shafts use a different U-joint from the steel ones.

 

The part number is included in the following link:

https://www.thirdgen.org/forums/tran...=carquest+alum

JamesC

 

The caps for the aluminum shaft are coated with something to keep them from corroding(sp)

 

Well, we took the rear end (3.32 pos) and the aluminum drive shaft from the 88 Formula so it wasn't mismatched years.

And yes, the u joint caps are different sizes on the back end of the drive shaft (I don't know why, but they are - the first ones we bought fit the drive shaft but were too small for the yoke in the rear end so we had to go back and get the right size, but that was a couple of years ago when we first did the swap).

The new stuff from JEGs will surely keep the bearing caps from moving again as the hardware will have to break first, the way it is made.

Thanks for the part numbers, we'll check it out.

 

Well, jacked it up to pull the old driver shaft (the back end was tore up pretty bad - it even lost one of the bearing caps in the driveshaft) and then saw the yoke on the rear end was busted, too. Most of one side was broke clean off and was missing. I guess we'll never know if the the u joint came loose and broke the yoke or if the yoke broke and then the u joint came off.

We have the yoke from the original rear end (91 RS, 308 7.5" 10 bolt).

Does anyone know if the spline count on the pinion shaft is the same for the 88 10 bolt and the 91 10 bolt? Thanks for the help.

 

No, the aluminum shaft uses a Spicer 1310 yoke instead of the Saginaw 3R.