RE: Rebuilding Tyco cars?
I've had the same issue. I couldn't separate it either, so I improvised... I decided to remove the stock motor, and cut the top of the diff case to accommodate the hobby motor I wanted to use. I haven't finished it yet. (Lol) I'm currently waiting for an esc to run the motor and servo. If I can't find one soon, I might be forced to use the electronics from my Slash "parts-truck". I'm using the motor guard from some random RC truck or buggy to cover and mount the new motor. I found it in my parts bin. I'm using a 540 style motor I salvaged from an old Dirt-Devil rechargeable vacuum. Let me know if you find a way to crack that diff case without breaking it.