The 16.8v diffs from the 3906 are stronger than what you just destroyed. I'm running a set unshimmed in my 3905 and they are better tha the stock diffs. They are an intermediate strength solution to this problem. The FLM hybrids are prob the best all around solution, but are pricey and need to be shimmed as pointed out. Go to Ebay and find the diffs for use in them, you can get them for about 1/2 as much than elsewhere.

Using buggy diffs will re-gear your EMaxx so be prepared to make a spur/pinion gear change to compensate.