Topic: Rear end Vibration

[SDWE61988]

The old blue trusty jeep has recently developed a nasty rear end vibration.  It is very bad between 1500 to 2000 rpm.  It shakes the vehicle and is almost deafinig inside while driving.  it has got worse over that last two weeks.  I recently fixed some loose and rusted exhaust pieces and then thought it might be the rear window or trim pieces in the hardtop.  I mentioned something to a fellow gear head at work and he suggested it might be u joints.  I tried the search function this morning here and did not find a lot of hits about u joints.  I have done a fair amount of engine work in the past, but not much driveline work or suspension work.  How do you inspect the u joints (properly) and how difficult are they to change?  Is there something else I should be looking at like the drive shaft or rear end?  This is a stock driveline and supension.  The axle is the stock D35 with the stock 4.10s.  Any input would be helpful.

[sharpxmen]

The old blue trusty jeep has recently developed a nasty rear end vibration.  It is very bad between 1500 to 2000 rpm.  It shakes the vehicle and is almost deafinig inside while driving.  it has got worse over that last two weeks.  I recently fixed some loose and rusted exhaust pieces and then thought it might be the rear window or trim pieces in the hardtop.  I mentioned something to a fellow gear head at work and he suggested it might be u joints.  I tried the search function this morning here and did not find a lot of hits about u joints.  I have done a fair amount of engine work in the past, but not much driveline work or suspension work.  How do you inspect the u joints (properly) and how difficult are they to change?  Is there something else I should be looking at like the drive shaft or rear end?  This is a stock driveline and supension.  The axle is the stock D35 with the stock 4.10s.  Any input would be helpful.

you could check the u-joint by hand (rotate the d/s back and forth when in neutral) - that would also tell how much backlash is in your R&P. lift one side of the rear axle so one tire rotates freely and go back under and rotate the d/s, will tell you if you have a  broken or chipped tooth in your rear. rotate the tire to see if there are any noises in the rear end.

I would think that is probably one of the u-joints or something diff related.

[SDWE61988]

Thanks for the info.  The noise and vibration is most often occuring during deceleration through that rpm range.   So when I rotate the d/s how much slack is considered normal?  I will have to crawl under there tonight and look around.

[oldjeep]

Also check to make sure that the pinion nut hasn't backed off.

[sharpxmen]

Thanks for the info.  The noise and vibration is most often occuring during deceleration through that rpm range.   So when I rotate the d/s how much slack is considered normal?  I will have to crawl under there tonight and look around.

should just be very little movement in the R&P. also what oldjeep said, see if the nut backed off or if there are any problems in the pinion bearings. you could also lift one wheel and have it idle with in the first gear and look at the d/s to see if it wobbles.

[SDWE61988]

Thanks guys.  I may not get a chance to look at it until the weekend ( thank god for multiple vehicles!)  I will update after i look at it.