Hey guys, this is my first post on here so bare with me. Two weeks ago I got a 3.5" Rough Country lift for my 98 Grand Cherokee. Install is all complete and now I have a vibration that I just cant figure out. It never did it before the lift, and it started as soon as I put it on. It starts dead nuts on 30mph, smooths out about 35, returns about 38 (at a higher pitch if you know what I mean), then smooths out at 45. I might feel it a little bit around 55 60 as well. Anything under 30 is totally smooth, and between 45 and 55 is too. If I let off the gas it goes away a little bit, but I think that's just because it slows down to a speed that it doesn't vibrate at. If I coast to a stop from 50mph, I still feel it at all the same speeds as when I accelerate. I replaced the u joints on the front and back of the rear drive shaft and nothing. I pulled the front drive shaft and test drove and still no change. I kinda ran out of ideas here so any suggestions will be much appreciated!
thanks ill give it a try. is there any way to check that without buying the new control arms? I think you might be right though. the RC control arms with that kit are like an inch and a half longer than the stock ones. you are talking about the rear LCAs right? not the front
Another option I suppose would be a transfercase drop.. but those have the adjustment your looking for. Seriously, do a search and you'll most likely find well written threads showing pics and drawings that'd help you understand. As well as your options.
You should not need a t-case drop on a ZJ at that height.
The pinion yoke of the diff should parallel with the t-case output at ride height.
Your description also sound like it's at certain RPM ranges that it vibrates. Have you checked your motor and trans mounts as well as your harmonic balancer?
1996 ZJ Green Laredo V8, 2.5" OME and Bilsteins, 33's, Holes drilled in the roof.
1998 ZJ Platinum Limited 5.9, Backyard parts fodder
1987 Mercedes 300D Turbo, the diesel daily, 30mpg in style
Originally Posted by Texas ZJ1
I heard someone yell "mall crawler" from the back porch. I'll go see who said that. Be right back.
I second that you don't need a t case drop. I had one on before I swapped transmissions and it vibrated at 45 mph. I decided to ditch it since I knew it was unnecessary once I had everything out. Now I don't have any vibes (knock on wood)