LOSI LST XXL Conversion ideas

[mistercrash]

A little while ago, the pinion and internal gears stripped in my rear diff. I repaired it thinking it was just what happens when you bash too hard. A couple days later, I blow the internal gears of my front diff and a pinion in the rear diff. I thought I was just unlucky. Yesterday, the internal gears of the front and rear diffs blew. This is a problem. I can explain pinions stripping if I didn't shim correctly but internal gears, there's not much I can do in there. I use the Losi HD diff cases so I'm baffled. What can cause the innerds of my diffs to strip so often?