I've got a 00 xj 4.0 auto with 231 and sye. The rear is shined at 6*. Im using the front shaft out of another xj. My problem is I keep throwing the u joint the middle giving me horrible vibes. With a new u joint I have no play in the shaft. And when I drive about 10-20 miles the vibes come back and I have slop

 

6 degree, looks too much, can you remove 3 degrees? Output and input should have parallelism, not necessarily point at each other.

 

So if I went with 3* shims would that help my u joint problem?

 

Remember with a SYE you need the rear to point at the transfercase not parallel. 6deg looks like its a bit much. What is that tubing looking thing that is in the middle of your driveshaft?

 

E brake cable. It looks like its on top if it in the pic but its no where near it

 

I was wondering about that lol.

Did you make sure that the yokes are good. No cracks or imperfections?

And if your angle is off... you will eat U joints.

 

Perfect I haven't went out and got a angle finder. I just took a stab at it and went with 6*.

 

try a 3* shim. im using a 2* now and it works fine. i can tell from the pics that your axle pinion is pointed up to much and it needs to come down some.

 

Ok will do

 

Can't believe no one mentioned this before, but have you verified that that drive shaft is balanced like it should be? A lot of times the balance weights that are/were tack welded on will fall off. Not a big deal when you're creeping around in 4WD, but when you've got it in the rear and you start going fast, it can cause vibrations. I agree, the axle may be shimmed a bit much, but also check your drive shaft balance.

 

could be but it wouldnt be eating thru u joints if it was unbalanced it would just be shaking. i have to take out my front shaft because its not balanced anymore and makes my jeep shake but never ate thru one u joint.

 

Ok since you mentioned that what would happen if I swapped my shafts around? I don't know if its balanced or not. I got it on Craigslist for 20 bucks

 

If I'm at 6* now the only place I've found that had 3* is rusty's and they are cheap but the shipping is outrageous. What do you guys think about 2 or 4*?

 

go to a local parts store and they should have them for cheap. check on the shaft to see if there is a little weight on it, you cant miss it. it takes some rock bashing to take those weights off since they are ment to stay on.

 

So I still haven't went and got an angle finder but I did take out the 6* shims and replaced with 2*. Kinda doing a trial and error kinda thing. I still think I need bring it up a bit more. Tell me what ya think