I have a 77' GMC Jimmy, I've change the engine to a new Mr. Goodwrench 350 and had both the tranny and the transfer case rebuilt. The probelm is that there seems to be a vibration when I reach a speed of about 50 mph to about 65. I took the vehicle back to the shop where the transfer case was rebuilt. The vibration seems to be in the stick shift of the transfer case. I was told to have the drive line balanced. I did but I still have that problem. Any suggestions.
It may just be chance that the vibration came about when you did the engine/tranny work. Does the truck have a lift and if so how much? If you are a do-it-yourselfer then you should check the u-joints. Also the rear axle could have something wrong with it. I'm just putting in new carrier bearings after a month of trying to diagnose a vibration as well. Good luck.
