Burgy

Put some new ujoints on, and now I'm getting a really annoying vibe above 60mph. I've got 2" OME HD springs on the rear with a 1" transfer case drop. I had some vibes with the lift before I did the transfercase drop a year ago, but it has been super smooth since then. Any ideas why this would be happening? I didn't think the driveline geometry would have changed that much with new Ujoints. Could I have installed a bad one?

I should note, I helped my brother in law move last weekend and drove almost 500 miles with a trailer. With the extra weight on the rear axle I had no vibes what so ever.

Slimgoaty

Well my simple guess would be something wrong with u joint install. If you didn't have them before, and that's the only thing you've changed....its probably that.

Burgy

But what would be wrong with the install? I had a bad Ujoint, I put in new ones, and now I have vibes, but don't have them when the vehicle has a load on it....

XJ-92

maybe try taking out the tcase drop and see what that does. otherwise i couldnt tell ya whats wrong with it

96xj4x4

are you sure they are in there tight? all c clips installed right? are the straps bent maybe to the point where they don't hold the u joint right?

what your describing with the vibration going away when under a load usually comes from your u joints having some side to side play and the centrifugal force accelerating holds it to one side so u don't feel it.

shadowman

Check the new ujoint install. I installed new joints and in the rush to finish(wife standing over me waiting to go to dinner), I over tightened one of the retaining straps. It was smooth as butter for about 150-200 miles and then developed a wicked vibration above 45 mph. Checked everything EXCEPT those joints...nothing. My teenage son asked if I could have installed the joints wrong. NO WAY, I was an ASE Tech! Long story short, pulled the retainer straps and the joint fell apart. New joint, torqued correctly, no vibes. Now I owe my son $5. LOL

Burgy

Good advice, I was in a hurry to finish them and didn't use a torque wrench. I'll go out in the garage and check that out after the game. I'm also going to hit them with the grease gun. My buddy that was helping me was supposed to grease the fittings before I re-installed it, but he says he's not sure if he did....

Burgy

checked straps, re-greased everything, installed driveshaft, and drove it today on the interstate. Guess what....vibes are still there.... Not at bad as they were, but they are still there. There is a slight angle at the yolk between the shaft and transfercase. I'm starting to think that this might be the issue. I've already got a 1" tcase drop. How much further could I safely drop the tcase? Quarter inch maybe?

shadowman

On the rear shaft, check the slip yoke for play. There was some issues with the later XJs getting a little too much play in them and creating a vibration. If you can wiggle the yoke around on the output shaft, that could be where the vibe is coming from. Either replace the yoke, or go with a SYE kit and get rid of the TC drop. Now the driveshaft angles...a single cardigan shaft should have angles that are equal on both ends (a cheap angle finder from Harbor Freight will do the trick). You can use angle shims between the axle and the leaf spring to adjust this. A double cardigan setup( like the front shaft) should have the pinion pointing directly at the output shaft of the TC. These are, of course, "perfect world", situations so I always try to get as close as possible to them.
Some of the more experienced wrenches may have a better recomendation.

leecarr

Some times one of the needles gets behind the end cap , you mite not notice it if that was the cap that fastened to the rear end yoke with a u bolt. I would suggest you take them out and have a look. I have replaced several almost new u joints lately. Most of them come from over seas and I think they 're made out of cottage cheese.

leecarr

Give your son the $5 and let him take your wife out for dinner. Never let your kids know your wrong, they enjoy it too much.

shadowman

Well, he is my son that wants to learn and has been handing me tools and asking thousands of questions since he was big enough to reach the tool cabinets. He says that its the first time he has seen me make a mistake. I told him that he hasn't been paying attention. LOL. I told him everyone makes mistakes. We must learn from them and hopefully not repeat them.

kjc

It's been a while since I replaced u-joints, but I remember you're sposta mark the driveshaft and pinion? yokes before disassembly so they are put back in the same orientation. Like they can be 180 out, if i'm describing this right. If not done it can result in driveline vibrations. I know it's a bit of a noob kind of mistake, but you did say 'in a hurry' and 'friend helping'

leecarr

I know exactly what you mean, my oldest son has been in the grease with me and my father since he was old enough to walk. Don't let them fool you they watch every move. The only thing is that things are starting to reverse know, I ask him for help and lots of questions. Keep em out there and stay proud.

Burgy

Thanks, I did make sure to mark the dshaft before I pulled it.

Ran into an even bigger problem this morning on the way to work, the blower motor quit working so I froze my a$$ off. I just had it replaced in July so my mechanic said its still covered under his warranty. So many issues with this Jeep right now.....