Buying a whole 3903 slipper setup off an ebay chop shop will probably be about the same price as just buying the back plate and pin.
Just got an entire 3903 slipper assembly on the bay, with a motor plate, a couple pinions, and even the plastic gear cover, for $22 shipped. Not a bad deal, got the pressure plate I need, and some extra parts I can use on my other maxx.
-Travis
Adults are just kids, with money.
Common sense, is not so common.