Make sure you dont have any broken leafs in the spring pack.
Sometimes they can split in half and be covered up by the brackets and crud.
It will look fine at first glance but they pull apart under accelleration and then go back in place when you stop
Also check out your transmission mount and motor mounts.
Any problem in the mounts might feel through the seat like diff is moving
If anyone ever did the trans they may have used an impact on the tranny mount which can pull the threads out of the case.
You should never use an impact on a trans mount but they do it anyway.
And, get the ass end off the ground and look for pinion bearing slop. The u joint can feel okay and the backlash can feel okay but bearing play will make the whole pinion shaft "wobble" under accelleration
Sometimes they can split in half and be covered up by the brackets and crud.
It will look fine at first glance but they pull apart under accelleration and then go back in place when you stop
Also check out your transmission mount and motor mounts.
Any problem in the mounts might feel through the seat like diff is moving
If anyone ever did the trans they may have used an impact on the tranny mount which can pull the threads out of the case.
You should never use an impact on a trans mount but they do it anyway.
And, get the ass end off the ground and look for pinion bearing slop. The u joint can feel okay and the backlash can feel okay but bearing play will make the whole pinion shaft "wobble" under accelleration