XJ with strange vibrations

Okay, I have been away from this BBS for a while now because I don't drive the cherokee anymore. :bawl: I have a long story, but gist of it is that I had a 2000 XJ for a few years. While I had it I put on a 3.5" rubi. sus. lift. I went off to school this past fall, and my mom decided she liked the jeep. She gets it, and I took the lift off and got new street tires. Now that the lift is off the jeep has a pretty substantial vibration that starts about 62-3 mph. I am not sure if the vibs go away at any higher speed. I am also not sure if it made the noise with the lift on because the tires were so load. We have taken the XJ to two or three tire shops to get it looked at, and had an alignment done since the lift was taken off. One tire place said the two front wheels were bent so we got new front wheels. The tires have all been balanced and all the bolts have been retorqued, and the jeep still has the vibration.

Now I am leaning towards something wrong with the driveshaft or possibly a u-joint. Does any of this bs sound plausible, and how can I tell if it is a u-joint failure? Does anyone have any suggestion or similar problems? Thanks in advance,

Mike

on a flat level surface, with the truck in neutral, engine off, tires blocked....

crawl underneith your XJ, grab the rear shaft and try to spin it either way.
Watch the Ujoints for ANY sign of looseness or slop. if there is none, check the front driveshaft, then the front axle steering Ujoints need to be checked as well, this can be done by gently prying on the joint with a screwdriver, observing any looseness or slop. also, an overlooked area of potential driveline vibration: the slipshaft on the front driveshaft. while under the XJ push and pull on the slider yoke looking to see if there is any looseness in the shaft.

If ANY wear is found in ANY of the u joints or slip yokes, they must be replaced.

Is there a slip yoke eliminator on the T case? How are your Motor/Tranny mounts? I know onetime in my "battlewagon" there was a terrable vibration caused by a shot tranny mount because it altered the driveline angle.

How did you return it to stock? With the original parts from that jeep?

good luck! darn vibration!!! :twak:

The long answer would involve a verbose description of why the new, "Improved" transfer case output for the rear driveshaft is not really an improvement over the old design.

The short version is that the new design is extremely prone to vibrations. My advice is to get a Rubicon Express "hack & tap" SYE, replace the driveshaft or have yours modified to work with the hack & tap, and I think that will probably eliminate the vibrations.

thanks guys for the responses

i'll have to check everything the next time i get home. Maybe i should have mentioned that the vibe sounds as if it is coming from the front. As for the parts, i solicited for anyone's old lower control arms, front coils, and shocks all the way around. For the rear I just removed the aal. Thanks again,

-M

Take the front driveshaft off, and see if that helps it. If it does it may just need greasing, or a new u-joint.

When I bought my 88 XJ it had been sitting for over a year. When I first drove it it had a terrible vibration coming from the front end. My first thought was, the front tires must have flat spots from sitting so long. After replacing all tires and having an alignment done there was no difference. I inspected everything to the best of my ability and found no problems. Only after reading an article on Cherokee Americas page did I decide to try new front wheel bearing/hubs. I did one side, it made it better. the next day I did the other, vibration GONE! I did find that the vibration was worst when driving straight. When I turned right of left, it dissapeared. Hope that helps