Not sure about the gear mesh, but if it had been off, the motor would have been way hotter than 85 after 3 or 4 minutes of bashing.

I've been running it recently with a rx pack, but i do have a regulator from MetalMan on my Ofna's 9918 that would do the same job as a UBEC.

The tranny thing sounds like more of a possibility, I'll have to check it while I still have the pinion off. BTW, i think the mesh was fine, but I didn't check last night, I just wanted to get the pinion off and see how many teeth it had.