My 93 XJ developed a weird vibration when I was driving home today. I installed my 3" lift over a year ago and only had a faint harmonic vibration, heard it more than I felt it. I had a bad toe problem in the front which resulted in my new tires wearing heavy on the outsides after 10k miles, so I had new ones installed yesterday along with an alignment. Drove home fine yesterday, fine all day today, but tonight I felt a vibration on the freeway. It can be felt under throttle, but goes away as soon as I hit the brakes. It came in under various speeds, even from a light. I went underneath the Jeep when I got home and played around with the drive shafts. The front had some play when trying to turn the drive shaft, the rear had maybe a 1/16" play. I tried playing around with the U joints and nothing moved. Anyone have any experience with something like this?

 

Do you have a transfer case drop and have you check for worn motor mounts?

 

no transfer case drop and motor mounts looked fine when I did the oil filter adapter gaskets the other day. I feel the vibration coming from the back.. when I was messing around with the drive shafts looking for play, I notice the transfer case would move up and down maybe 1/8" to 1/4", but I imagine that's normal for taking bumps and whatnot

 

the vibration came back at random this morning again. not sure what sets it off

 

If it's in the rear check the joint again maybe remove, clean and inspect. How's the rear? tires? brakes? everything good 'n tight?

 

Make sure all your steering components are nice and tight too. I had a little bit of a wobble up front and tightening up the track bar seemed to get rid of it.

Might not be your problem, but it can't hurt to check right?

And if you're wobbling in the back... well there's really nothing back there that's moving apart from a driveshaft and wheels, so one of those would have to be the culprit.

 

well I took the Jeep to a drive line shop and after them looking it over, they determined my drive shafts and u joints were all in great condition. they did however find that my trans mount is shot along with my driver side motor mount and the right side upper control arm bushings is shot as well from all the oil i let leak on to it for too long before replacing the oil filter adapter gaskets. I went to Napa and get two new motor mounts, trans mount, and two new upper control arm bushings for about $85 including tax. The drive line shop ended up not charging me for anything

hopefully replacing these will get rid of the vibes and somewhat lower mpg..

 

That's good news, hope it works out for you