So I was bashing around on my street and had made a few jumps with the snow left over from the recent storm and I started noticing a grinding or gear clattering sound when I hit the brakes. You can hear it over the sound of the motor idling and it does it in either forward or reverse. It doesn't make any noise (at least not that I can hear) under power - only when you hit the brakes and stop. As soon as the truck stops, no more noise.

if I roll it on the ground with the motor off, it's nice a quiet. if I roll it and then hit the brakes - clatter. I checked the clutch bell/spur gear mesh and it's fine.

This is a new Revo 3.3 with stock TRX motor. I installed FOC conversion and close ratio gear set, and 40 tooth spur with stock clutch bell housing. It also has the vented rotor and a brushless servo operating the brakes/throttle.

Did I damage the ring and pinions by jumping the truck over the jumps I made with snow? One jump is about 3 ft high and the other is about 10 inches high. Nice smooth landings for the most part.