Be careful when replacing the diff outdrives with aftermarket ones. I discovered that Associated changed the design of the diffs between the first series and the latest. I too fried the plastic diif outdrives in my factory team kit and as a quick fix, tossed in the old ones from my original racer kit. When I got around to replacing them with Hardcore Racing outdrives, I couldn't get the diffs to work. I later discovered that one of the internal bearings (racer kit) had been replaced with a narrower bushing (FT kit) and made all the difference in the world. It kind of sounds like you may have the same problem, the aftermarket parts are a different generation than the the ones that fried. If that's not the issue, email IRS and ask them for advice, could be something simple. Hope this helps, good luck.