I get a significant vibration in the drivetrain when I let up off accelerator. Vibration nonexistent when under load. Several years ago some moron replaced clutch. Related problem? UJoint? Flywheel? Rear-end? Clutch??

 

Probebly U-joint. Could also be the crossmember rubber mount or your hanger bearing on the extra cab trucks. If it is a very light vibration I found it was always the rubber mount.

 

Could be a u joint or the output bearing on the transfer case. Got a bad one in my 87 P/U 190k. Check to see if its throwing oil on the bottom of the truck. If it is you'll have to repace the bearing & seal.A bad bearing won't allow a new seal to work effectively becauce the output shaft is wobbling. And this is were the vibe comes from.

 

Thanx for the help guys.

 

mine did something like this and it was not the u joint. it was the carrier bearing. not in the rear end, in the middle of the driveshaft. the driveshaft also turned out to be bent or unbalanced or whatever the case was. it tore up my ring and pinion eventually. get it taken care of.

 

Update - It's the output bearing on the transfer case. Thanx guys

 

Was your transfer case leaking? Mine leaks moderately, and I do have a wobble if I'm off the gas at highway speeds. I always thought it was from my worn front tires or alignment.

Rob

 

Leaking only in the sense of throwing gear oil onto the bottom of the truck.

 

No mine leaks gear oil onto the ground.

Rob

 

Mines doing the same exact thing. U joints dont have any play, how can you tell if its the output on the transfer case and how hard is it to replace the bearing?

 

rdlsz24...Sounds like xfer case ouput shaft oil seal. As far as the bearings go, I'll let you know how hard it is tomorrow nite.

 

Wasn't bearings after all. The shady shade tree mechanic who changed the oil seal last didn't but the flange to spline nut on right.