I stripped the 68t spur gear on my e revo and have put the 54t replacement one on that came with the truck. It now makes a very strange sound like a high pitch squeal. I have pulled the gear box out and checked all the gears in it and run it without the drive shafts connected to rule out the noise was diff related. I am new to electric but have run a t maxx for years. Any help would be appreciated.