1717 vs LST XXL diff

[mistercrash]

Looking at the pic of your broken diff case, I can see that you shaved some material in the right place to fit the diff in the E-Revo bulkhead. But it looks like you also shaved some material where the screws are which I think, this is just my opinion here, made the diff case a little too weak in the front where the pinion shank is. The case cracked, the bearings of the pinion started wobbling a tiny bit making the pinion move slightly until the pinion stopped meshing correctly with the ring gear and that's when it all failed. Also, did you shave off just a half a mm or more than that?
I measured a stock, untouched LST XXL diff case and the thickness is 26.85 mm. If 0.5 mm is taken off on each side than you should be left with 25.85 mm.