Lost in one of the rebuild threads discussing the LST2 diff mod I had stated I was on a quest to try aluminum diff cups and beefing up the bulkheads first.
Problem is finding a diff cup that will actually work without having to grind down the cross support for the spider gears. Ive seen several HR cups where folks ground down the cross support to get it in ( I ordered some of those too but retunred them) and just to let everyone know I odered up a pair of RDlogics and guess what, they use the same cnc program and got it wrong too in the same aspect.
While I was building the diffs for my over powered slash 4x4 I used FLM cups and the ERBE internals with the exception of the ouput gears and shafts. I was mistaken when I said that the shafts were a different diameter (thats right, I was wrong so if you are gonna bloat now is the time to do it becasue it doesnt happen often! LOL). They are in fact the same diameter with the only difference being the machining on the end where the shafts connect. All else is identical. So I just finished building two diffs using FLM cups for a slash 4x4 as you never see the cups listed for the ERBE with the exception of the modified version with a different ring and pinion gear and they are never in stock anywhere. The cups fit perfectly and shimmed great.
So if you are having a hard time finding aluminum diff cups that actually work and need no grinding of the cross support look up FLM diff cups for slash 4x4.