Driveline Guru's

Weird problem.

here's the rig were dealing with so u know specs. 88 XJ AW4, 4.0, 120k, 2.5inch or so lift 31's w/ 3.55. Ok, time for problem. Also I have never had any vibe probels due to lift height or anything for over 8 months, and think it's strange now that they'd be acting up.

I noticed driving around town that when I get up to around 25-35 mph range there is a weird vibration like the hole vehicle starts to vibrate. It shifts real smooth through 1 to 2 and haven't had it up to speed yet but assuming 3 to 4, but right at the end of 2 to 3 where 3 pics up it shimmies. I guess shimmy is a better word to use. I checked the driveshaft U joints they are fine. I also check wheels to make sure I didn't throw a wheel weight. Fluid is fine and full as usually. What could the problem be? bad third gear in a 16 year old tranny? I'm open to any and all suggestions. FWIW I dont' think it's TPS seeing how it shifts properly in any other range

btt

please

It could just be a blown belt in one of the tires, It happened to me and the only reason that I knew it was that is after 4 months of a shimmy it finnally gave out, I replaced the tire and now more shakey shake...

I would get my front wheels balanced. 9 times out of 10 this seem to cure any shimmy in my xj

Rotate your tires and see if that makes a difference.

Other things to check would be all joints and TRE's. Have a friend move the wheels back a forth a little (just enough to make the tires move an inch either way) while you feel all the moving joints (careful not to get your hand caught!), if you feel any popping then you should replace it. Also check both ends of the trackbar while doing that.

Check your unit bearings too, lift the wheel off the ground, grab the tire from 12 o'clock and 6 o'clock and try to move it back and fourth, if there is any movement at all the bearings are shot.

If you do these (and find everything good / still the same) then I'd move along to the driveline, try removing the front drive shaft first and runnine, see what happens (that one is easy, just pull it). After that you could remove the rear, but you'll have to devise a cap for the slip yoke area, once you remove your shaft it will puke fluid out of the transfer case.

Also, when removing drive shafts, mark them so that you put them back in the same as they came out.

Sequoia