Under heavy acceleration and the tranny shifts it feel like the whole driveline jerks to left..maybe right...idk but it feels like it jerks sideways. esspecially when its shift into OD. I went under the truck and grabbed a hold of the driveshaft right after it leaves the tranny and jerked it back and forth and the tail of the tranny actually moved back and forth with it. I feel like it shouldnt move around with so little force and can only imagine how much movement it goes through when it shift. Is this movement even bad for it?

 

when i said i jerked the drive shaft back and forth i really meant side to side.

 

push on the rubber transmission mount with your finger, it should be firm rubber. if it feels like a gummy bear then it is shot. also, grab the tail shaft of the transmission and push up on it while watching the transmission mount and look for movement.