The guy from ebay says that the rear diff is a GPM but i couldn't find a rear diff made by GPM for the Micro RS4. Anyway, I oredered a new Solid rear spur set-up from Towerhobbies. I'll see how that works out. I dont want to send it back and I dont mind trying to figure it out. It's all part of the game. Just wanted to see what you guys had for me in terms of getting this issue resolved. Thanks