V120D02S Spinning (NOT DEVIATION RELATED)

I just got this helicopter today, and on the first take off it went up and back about 4 to 5 feet kind of diagonally, then just started spinning uncontrollably to the left. I checked everything and realized that when holding it and throttling up, the rear rotor spins till a certain point, then stops... There's no friction on the rear rotor when manually spinning the main. The gear that's connected to the shaft stops turning - which means that whatever connects the shaft to the motor is stripped. Has anyone else had this issue - or have any suggestions on fixing it, rather than shipping it back?
I posted this over in the RCGroups forum, but have found that people over here are incredibly helpful and knowledgeable. So if anyone can help me, I would really appreciate it. Sorry if I'm not supposed to be posting non-Deviation stuff here.

Thanks!

Why would you ship it back? If you wanna survive in this hobby, you have to learn to diagnose and fix them as well.

Look at the exploded view of this bird and use it to replace/verify the tiny gear under the main gear.

Oh also... wowhobbies.com for parts. They're located in Orange, CA and are fast at shipping and you can pick up locally if you want.

Sorry, I know that post didn't belong over here. It was the B gear. It was stripped on the inside. (The "D" was an "O")