[THEFERMANATOR]

I know you need a 93+(not sure if 91-92 will work or not as I can't remember exactly when they changed crankshafts). The counter rotating lowers are simliar, but a bit more work to get the gear carrier out of due to the different design for holding it in. A right hand rotation unit has all the thrust going forward from the propshaft and the gears whereas a lefty has the prop thrust going forward and the gear thrust going aft. This requires a different gear holding assembly that holds in tighter so that it doesn't tear the gears up. I've replaced just the seals in them in the past though without much disassembly of them. If your careful with a cnter prunch and small rounded screwdrivers you can pry the prop shaft seals out without removing the carrier assembly. I'm pretty sure the upper driveshaft assembly has to come out though, but there not normally seized in that badly.