# driveline (I think) vibration



## bwm1 (Feb 27, 2008)

I am experiencing some pretty heavy vibration when I drive over 35 or mph, and some clunking when I get on and off the gas.

I have checked the u-joints, and they seem pretty good. I have checked the center support bearing, and I can move the driveshaft around approx. an inch in any direction. How much movenment should there be in this rubber supporting the bearing? Is there a way to test if the bearing is ok. The rubber seems intact.

Thanks

edited to add: '92 2wd.


----------



## Abeerdrinker (Jan 8, 2008)

I started to get the same thing recently as well. I know its my fault cause when I moved to GA. I weighed my truck on the scale with a GW of 7100 lbs. My truck took a beating towing that much for 1200 miles in one straight shot. Now my truck grinds as if the drive shaft or rear diff is vibrating or shaking


----------



## Oldnissanguy (Jan 6, 2005)

That seems like a lot of play to me but I don't know what the actual spec is. Vibration could be caused by anything like a tire out of balance or out of round. 

Try putting your truck on a lift to see if you can isolate the source of the clunk.


----------



## dvdswanson (Nov 6, 2005)

check the rear diff see if there is any play in it. also check the tail shaft housing.


----------



## smj999smj (Jan 1, 2006)

The insulator of the center bearing support should keep the driveshaft close to center of the support assy. If the rubber insulator is torn or collapsed, it should be replaced. 
Running the vehicle in drive with drive wheels off the ground, a stethoscope might help in isolating a noisy bearing. Otherwise, the only way to test it would be to unbolt the center support and rear U-joint and spin the center bearing around the shaft, feeling for binding or roughness. You will likely have to remove the metal bracket around it as it's pretty tight clearance. You could also remove the whole driveshaft assy. and do the same. That would also give you a better opputunity to check the U-joint for possible binding in their movement. The clunking would suggest that the problem may be in the differential, however. A bad tire or tires obviously won't cause clunking, but could cause a vibration issue.


----------



## lumbee (Mar 20, 2005)

...I was having a problem similar to you guys. My problem was the tranny. I was only getting it in 5th gear, so probably not for the guy saying it is over 35mph. For the other guy, try staying in 4th gear, then shifting to 5th, and see if theres any difference. I did the same with my truck...did alot of towing in 5th gear, and that screwed 5th gear up...I have a thread on here about it. 

...that sounds like alot of play in the center bearing...if u'r saying you can actually raise the shaft off the center bearing, then I'd say thats u'r problem...


----------



## smj999smj (Jan 1, 2006)

He's not saying that he is raising the shaft off the center bearing, only that there is an inch of movement in the rubber support of the center bearing assy. If the center support assy. was brand new, one would be able to grab the shaft and move it an inch up and down. The problems arrise when the rubber support tears or collapses letting the driveshaft lay at the bottom of the support assy. rather than near the center of it.


----------



## bwm1 (Feb 27, 2008)

*re*

Thanks for the feedback, I don't have a garage, and its been too cold out to jack it up and get under there to have a real good look around. Hopefully this coming weekend I can get at it.


----------

