i have 2001 surburban 1500 4x4. diff. went bad 2000 mi. ago . i rebuilt it with everythng new. i have vibration at 65mph&higher. it does not matter if i am under power or coasting in neutral. i had drive shaft checked for straightness and rebalanced with new ujoints. problem still there. took rear drive shaft out and drove it down road on just front shaft and vibration was completly gone. do you think it could be in transfer case or still have problem some were else.
hunterjo

 

Seems that it would still be there considering you're using the transfer case to drive. I'd start with checking the rear drive shaft u-joints.

 

When the rear driveshaft was installed after the rear end rebuild, was it put back in the same position it was in , prior to the R&R? If the rear driveshaft is out of phase, it would vibrate. You could look at getting an on vehicle balance and see if this helps.

I am sure that you are pulling your hair out trying to figure out the vibration.

 

still have vibration problem. have another question how much run out are my drive axles allowed to be out of round? i have .030 on one side and .045 on other side.