Vibration

LibertyCRD · **Posted:** Sat May 07, 2011 9:22 pm

OK, so help me find the problem before my KJ ends up at the bottom of the Ohio River.

I have vibration that starts at about 55 MPH.. It keeps vibrating the faster I go from there.

I've tried:

3 different sets of wheels
4 different sets of tires
3 balancing/rotations
2 new U-joints in the rear driveshaft
Inspected front driveshaft and all joints appear in perfect health
New passenger side CV shaft and intermediate shaft, remanned from NAPA
New rear parking brake shoes
Relatively new front brake pads
All calipers greased and inspected, seem to be fine

I'm out of ideas. Please help. It's vibrating bad enough that you can't just ignore it and go on. Trust me, I try. :furious:

patmaz · **Joined:** Sat Jan 01, 2011 2:52 pm **Posts:** 134

When was the last wheel alignement ?Might want to check that out :wink:

tjkj2002 · **Posted:** Sat May 07, 2011 11:00 pm

--Balance front/rear driveshaft
--Front wheel bearings
--Rear axle bearings
--bent rear axle(slight)
--Bent CV axle
--Worn bushings,all suspension
--Grease rear driveshaft slip yoke
--Worn motor mounts
--Worn t-case/trans mount
--Trans problem(internal/external)
--Engine problem(internal/external)
--T-case issue
--Lift causing vibs
--Bad set,or missing, KJ's "Balls",rear axle
--Exhaust issue

Just what's left off the top of my head.

LibertyCRD · **Posted:** Sun May 08, 2011 10:18 am

Ok, well I did already greased the slip yoke, inspected the front wheel bearings, and tightened the motor mounts. So I think since they are cheap, I'm going to replace the rear-most U-joint again just to eliminate that obvious possibility. If that doesn't work, I'll go ahead and replace the front driveshaft CV (I have one waiting) even though the boot is not ripped. Then I'll check my TC bolts to make sure they aren't backing off.

Isn't there a way to check the TC bolts without dropping the tranny? There is an inspection cover on these bellhousings, right?

tjkj2002 · **Posted:** Sun May 08, 2011 7:39 pm

LibertyCRD wrote:

Ok, well I did already greased the slip yoke, inspected the front wheel bearings, and tightened the motor mounts. So I think since they are cheap, I'm going to replace the rear-most U-joint again just to eliminate that obvious possibility. If that doesn't work, I'll go ahead and replace the front driveshaft CV (I have one waiting) even though the boot is not ripped. Then I'll check my TC bolts to make sure they aren't backing off.

Isn't there a way to check the TC bolts without dropping the tranny? There is an inspection cover on these bellhousings, right?

I would remove the front driveshaft and drive it,if vib is still there re-install front driveshaft as it's not the front driveshaft.Then remove rear driveshaft and put t-case into part time 4wd(do not use full time,you will not move) and drive,if vib is still there it's not the rear driveshaft.

LibertyCRD · **Posted:** Mon May 09, 2011 9:59 am

I'm starting to wonder about the rear bearings. Pinion bearing in particular, but maybe the others too. Hmm.. The driveshafts don't seem to have much effect on this.

KJ Willy · **Posted:** Mon May 09, 2011 7:16 pm

When my front bearings were going out they test fine, no shake or looseness in them. once the passenger one came out it fell to pieces.
Does the vibration get worse or better when turning?

WolverineFW · **Posted:** Mon May 09, 2011 9:44 pm

You said you tightened your motor mounts, but I would suspect they could still be bad even after tightening. I believe a few others said once they got them out was when you could really tell they were shot. Just another idea since the CRD ones seem to be somewhat hit or miss in longevity.

LibertyCRD · **Posted:** Tue May 10, 2011 7:34 am

KJ Willy wrote:

When my front bearings were going out they test fine, no shake or looseness in them. once the passenger one came out it fell to pieces.
Does the vibration get worse or better when turning?

I'm not sure that I can tell much difference when going around a curve. But something that I do notice is a little bit of "shimmy" in the steering wheel. The fact that I can feel the vibration pretty well through the steering wheel could mean that the problem lies in the front end somewhere.

Hmm.. I do wonder about the wheel bearings. They have 101,000 on them now and they've had larger tires on them for the last 26,000. Perhaps even though they passed the inspection one of them could still be going dead on me?

tjkj2002 · **Posted:** Tue May 10, 2011 11:36 am

LibertyCRD wrote:

KJ Willy wrote:

When my front bearings were going out they test fine, no shake or looseness in them. once the passenger one came out it fell to pieces.
Does the vibration get worse or better when turning?

I'm not sure that I can tell much difference when going around a curve. But something that I do notice is a little bit of "shimmy" in the steering wheel. The fact that I can feel the vibration pretty well through the steering wheel could mean that the problem lies in the front end somewhere.

Hmm.. I do wonder about the wheel bearings. They have 101,000 on them now and they've had larger tires on them for the last 26,000. Perhaps even though they passed the inspection one of them could still be going dead on me?

Do you have the OE UCA's? That could be part of your issue as your caster maybe not enough or to much.I'd also check your R&P mount bushings,if one or both are torn it can cause a vib at higher speeds.

LibertyCRD · **Posted:** Tue May 10, 2011 2:09 pm

yes, I still have factory UCA's. I've had alignment done twice at two different shops and both said I'm in spec.

I grabbed the outer steering links at the spindles and both rotate obviously, but they feel tight and I don't suspect them of failure. I have not checked the actual rack and pinion yet, or the inner link. They are hard to get to on the KJ. I'll try to check them later this afternoon.

Thanks for the tips so far. I'm really wanting to figure this out before something fails and strands me.

LibertyCRD · **Posted:** Wed May 11, 2011 7:39 am

So I'm up under the Jeep last night looking at the steering rack and checking out linkages, and I notice grease on the outside of my passenger side CV boot. Look a little closer, and there is a hole in the boot!

I just put that CV shaft in less than 2 months ago, and I haven't been offroad yet! And it's already got grease coming out of it from the hole in the boot and also from around the band clamp! To feel the boot with the hands, you can clearly tell that the rubber is a WAY lower quality rubber than the boots on the factory shaft. NAPA garbage... there is a reason why I haven't shopped at NAPA in 15 years. I guess I needed a reminder.

So, I get to call them up and fight with them over this crappy shaft plus labor reimbursement because these shafts are some of the more difficult ones I've ever pulled on IFS. And all the while, I've still got the vibration. I'd like to pull the engine and roll the rest of the Jeep over a cliff somewhere.

infernicus · **Posted:** Wed May 11, 2011 5:27 pm

I replaced my passenger side CV with a re-manned NAPA one and the same happened to me It is true that the NAPA boots are thinner than the MOPAR ones, but it is possible that with the re-installation, the boot was pinched, not all the way through, but enough to tear through with use. I replaced them with the MOPAR ones after that.

Its also been said that there is too much grease/air in the boot, and to relieve some pressure before installing.

You can also do what I did, it worked pretty good! lol.

Good Luck

Vibration

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