I'm with Swathy. Even though the gear boxes may seem fine, metal gears are tight and the casting isn't the best. I questioned if I really needed to break in gears when I got mine, and this weekend made a believer out of me and I am glad that I did. I visited my sister and my nephew took out the Bulldog I bought him for Christmas. I didn't break in the gear boxes before giving it to him and tried pushing his tank while it was turned off and couldn't get it to move. Mine will roll with a push by a couple fingers and not much effort. your left side gears may be just a little too tight, or there may be a flaw in the casting somewhere that is causing the problem. Read the FAQ section and give it a try. Not a hard procedure and well worth the time. I looked and couldn't fine a gringing compound anywhere and just used a gritty toothpaste and it worked fine.

You may also consider getting the steel gears that RCCommand offers. $37 and they are pretty awesome, better quality, and quieter from what everyone that has them says.

Sorry to hear you are having problems & good luck with it...