I've got a 2005 Avalanche with a vibration that comes in at 60mph,the vibration can be felt in the whole truck. It doesn't care what gear that it's in, as long as I am accelerating. Coasting , I don't feel anything , even at 80mph. I've replaced the universal joints, and the engine mounts are OK. I had the rear end cover off when I replaced an axle seal, and there wasn't any sign of damage in the differential. There is little doubt that the vibration is being caused by the driveline, but I'm not sure to put the blame, my guess is the differential but I can't say why. Is there any history of these causing trouble like mine ? Has anyone seen a problem like this being caused by the transmission ????

 

Didja bend the shaft? Probably need to rebalance it.

 

There isn't any damage to the driveshaft, and they don't just decide to go out of balance. I was expecting for someone to tell me about a chronic problem that is common in the differential.
Both of the U joints are free and not binding, so no problem there.......??

 

did the problem start after ujoint replacement?
are the dshaft balance weights still in place? have seen people knock them off during ujoint install.
aluminum or steel dshaft?
the only thing that changes during an accell is pinion angle and pinion bearing load. is the truck lifted? if yes, how extreme is the ujoint angle in degrees?


there is a phone app vibration analyzer that can measure the frequency....the frequency is different for axles/tires and the driveshaft.

 

(to continue this thread since OP abandoned it) yes, I replaced u joints and now there is a vibration specifically at 2000rpm.

the first time I replaced the u joints using a sledgehammer, which made the bearings fall out. Replaced them again using my brothers impact press tool, went in smoothly.

I believe I may have bent the driveshaft the first time. But why specifically at 2000rpm and not higher? Speed won’t matter either, could be going slow or fast.

One more question, I hear a lot about drive shaft “indexing” or “phasing”. People say to rotate 180 to stop vibrations but it looks like it doesn’t matter how it gets installed.

also forgot to mark drive shaft when removing so I wouldn’t know the correct position anyways, if any.

Any help would be greatly appreciated.