Still haven't been able to get me hands on a buildsheet, looking to figure out what rear end is in this thing, I know it's locking with 3.42 gears but I need to change the diff fluid. All searches keep coming up with a gm 8.5", 10 bolt. I also see references from time to time for a gm 9.5" rear end, anybody know if that is an option. This tahoe has a 12 bolt rear end. All u want is to get a stinking different gasket for this thing. Thanks in advance.