Just got a tmaxx classic 4910. Was told it has been sitting for awhile. Got it started but would only run at real high rpm. When it did run the tires would spin as soon as I started it. I decided to replace the motor and upgrade to the 3.3. I put motor in and it starts fine when you give little gas it does not move. when I pinch gas line to turn off it goes to a high rpm and tires want to spin then it dies. I gave it some gas when it was running and it just wanted to buck forward. Spur gear moves freely in both directions when motor not running. When running doesn't move in forward or reverse. Spur gear is meshed perfectly on clutch bell. Any help would be greatly appreciated. Thanks