groan/vibration while slowing down

Ok, so over the last year or so I've been getting this groan/vibration when coming to a stop. Lately it has been getting worse. When slowing down, it starts at around 15mph all the way to a complete stop. I assume it's a bearing, but I can't track down which bearing. I checked all the u-joints (replaced several) and they are fine. Front wheel bearing/hub assemblies seem tight, and rear wheel bearings seem fine. I'm starting to think it might be a carrier or pinion bearing…. I don't want / can't afford to just start replacing bearings at random hoping to fix the problem. Any ideas of where this groaning/vibration might be coming from????

'98 xj, 4.5" RE lift, t-case drop, 242 t-case (no SYE,) D35/D30, 3.55 gears, AW4, 31x10.5, 15x8 4.5" backspace wheels, 125,000 miles.

I'm having the same problem exactly, it sucks!
please help!
also whats a resonable price on a high pinion d30 used?

i was recently having this problem on my lifted xj. pretty sure it was the steering arm being loose on the box in conjunction with shaft play. have a new box and will be putting it together this weekend, will post updates...

With 4.5" lift and t-case drop this might not be your problem but your can start seeing this about 4".
If it happens when you are breaking it could be the front ujoint on the rear drive line binding. The stock slip yoke does not have the best working angle. When you break the rear will lift a bit and increase the angle. It will work fine when sitting level but the slight lift could be enough to start binding.
You can check this by jacking up the rear by the frame so the axle drops as much as possible withe wheels off the ground enough to turn. Then turn the rear wheels and watch the front joint on the drive shaft.

DaveW said:

With 4.5" lift and t-case drop this might not be your problem but your can start seeing this about 4".
If it happens when you are breaking it could be the front ujoint on the rear drive line binding. The stock slip yoke does not have the best working angle. When you break the rear will lift a bit and increase the angle. It will work fine when sitting level but the slight lift could be enough to start binding.
You can check this by jacking up the rear by the frame so the axle drops as much as possible withe wheels off the ground enough to turn. Then turn the rear wheels and watch the front joint on the drive shaft.

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I've had the lift on for about 3 years now, and the noise has only reared its head in the last 10-12 months. I don't have to be on the breaks for it to occur; it will do it while coasting to a stop....

I **think** it may be coming from the front, so I may pull the front drive shaft out to see if that makes any difference...

Ok, so I was looking the jeep over this weekend and I noticed the front left tire was severely cupped on the inside half of the tread. So I started tearing into that side to see if I could find any loose parts. The hub/bearing seems fine, no play and spins freely. Steering seems tight. I put the front axle on jack stands, and put a high-lift under the rotor to put slight pressure on it to check the ball joints. Looks like there is maybe a 1/16" of play…how much play would be considered acceptable? I would assume there should be no play, but I wouldn't think that 1/16" play would cause the tire to become so badly cupped.

I moved the front tire to the back and put it back together. Went in and took a nap (I've got the flu.) Drove it this morning and the "groan" that I was hearing is still there, but not as noticeable and is now seems to be coming from the rear. The vibration is virtually gone as well so I assume the groan/vibration was caused by the cupping on the tire.

Is the 1/16" play in the ball joint enough to cause the front tire to become so badly cupped on the inside half? Or should I be looking for another cause? I think I'll go ahead and replace the ball joints in the next week or two, and maybe replace the tie rod ends then have it realigned.

It seems like the ball joint was causing uneven wear on the tire as it controls the camber angle. There should be NO play in balljoints just FYI.

Depending on how long the ball joints have been like this, they could have caused the wear on the tire which led to the noise/vibration. If there is uneven tread pattern you would definitely feel/hear it at lower speeds.

MoparManiac said:

It seems like the ball joint was causing uneven wear on the tire as it controls the camber angle. There should be NO play in balljoints just FYI.

Depending on how long the ball joints have been like this, they could have caused the wear on the tire which led to the noise/vibration. If there is uneven tread pattern you would definitely feel/hear it at lower speeds.

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Thats exactly what I thought, thanks!

I can almost guarantee its an axle bearing in the diff. My dads was doing it for about a year also and we just found out what it was, were replacing all the bearings in the front end its being done for about 300 total

nevermind I should have read the rest of the thead before diagnosing. It might not be the axle bearings