I was wondering why I didn't have this prob - I'm slowly getting a FLM extended E-Maxx put together using hybrids/UE diffs and I did not have this prob at all. I have the proper amount of play with the supplied extended rear bone and the UE TI front bone.

I used UE drive cups on the diffs and the trans and this is apparently why I didn't have this prob. I guess this is a solution of sorts if you don't want to grind on the bones to get your clearance.