Ape stit

Im having a lound humming vibration after 50 mph from the rear end, only on acceleration and maintaining speed, if I let off, it goes away. I just traded my other jeep in for this. does anybody know what kind of drive shaft this is. Do I need to shim the axle to get rid of vibe, and if so do I shim it up or down?
Thanks

a1racer

nice looking jeep and i would put a 3degree shim on to help with the angle on the rear end and that should help fix it

ol"blue

Your pinion bearing's probably the cause of the noise. Looks like the seal has been leaking, caused by the bad bearing having play. JMO.

4.3L XJ

You don't need any shims. It has already been done. Your drive shaft on the top end is a double cardan, or some call it a CV joint. When you put this type of shaft in, the idea is to tip up the pinion so it is as close as possible in alignment with the rest of the shaft. This is what a lot people end up doing when they lift an XJ and have rear drive line vibrations. I agree about the pinion bearing. Check the pinion for play.

Ape stit

Yes it has been leaking, I took the cover off to change the fluid and check for metal shavings but there was none at all, not even fine powder shavings. There is no shim in it now, I was reading something where the pinion should be pointing at the rear of the transfer case when you put this drive shaft on, as of now it is aiming at the transmission, so it is a little low, it is not inline with the driveshaft. Ill change the bearing and seal and see what happens. are all shims in that 40-50 dollar range?

Ape stit

No there isnt any play in the pinion when I try to shake it with the drive shaft removed