I just replaced my leaf springs in my 2001 XJ. When I did this I also added an add a leaf for towing. I now have a vibrtion only when accelerating. I have been reading on hear that the my drive line angles are most likly off. I was wondering if any one else has done this and what you did to fix the problem. Thank you for your help.

 

how much lift do you have?

 

I used new stock spring packs the 7 inch arch heavy duty from Quadratecand a add a leaf. I am not sure how much higher than stock it is but with stock tires it is 34 inchs from ground to the bottom of the fender flare.

 

After replacing my rear leaves with new stock leaves, it was 33" from the ground to the bottom of the flare (before settling). So I'd say he's at something like 1.5 or 2 inches of lift.

 

Normally at that little of lift it shouldn't make a difference, but try a tcase drop kit. It's only like $30 online and will fix your angles and eliminate vibes at lower lift heights like yours

 

I will look in to doing that.

 

The slight difference in pinion angle could be just enough to blow out a "almost" worn out u joint. If your u joints are old i would change them to see if thats the prob. You shouldnt need a t case drop but if you do drop it be really careful with the. CRossmember bolts, ive broken all 4 and they are hell to drill out.

 

Had this same problem when I switched to Rancho 1.5" springs. Check your u-joints, mine was completely shot

 

I double checked my u joints and they are good (I did replace them a few years ago). I also rechecked my height it is 20.5 inches from the center of the center cap to the bottom of the fender flare and 34 from the ground to the bottom of the fender flare.

 

Most accurate way is from top of axle (not diff) to bottom of frame rail. Stock for rear is 6.5" I THINK! Pretty sure front is 6" even. But I needs to do the double check on that..

How did you check u joint?

Edit- correct measurements.

 

I will get that measurment tomorrow. To check the u joints I lifted the rear end and rotated the drivshaft in both directions also trided to move it forwards and backwards there was no movement in any direction.

 

Stock height from the center cap to the flare is 17" (or maybe 17.5 I don't remember exactly) so you're at least 3" up in the back which can give you vibes. Do you have any lift in the front? An xj would look pretty funky with 3" in lift only in the rear

 

XJ on flat ground/not running, block tire, put it in N, apply ebreak, crawl under and try to spin shafts.