I recently got a second mini to mess around with while I’m building my other one. I decided to lower it about 4 in in the back to even out. The other day I busted a U turn and noticed that the truck shifts to the right when changing gears and when accelerating it shifts to the left. Yes I know that sounds weird. I also noticed it has a vibration at 45 mph and the axle has shifted over to the passenger side slightly. I’ve taken the rear end apart and put back together as straight as possible but nothing changed.

 

That's a weird one... If you're using blocks to lower the rear, did you make sure the holes in the blocks go all the way down the centering stub to the leafs?! Make sure you're tightening to oem torque specs.. make sure the shackles aren't loose.

 

Checking for loose u-bolts and shackles and their bushings would be my first areas to inspect if you just added a drop