It's fine, it should spin and spin. Now you have to pull the trans out and open it up. Leave the engine out for now, slap it back in once the trans is done. If theres nothing wrong in the trans, it was your mesh. Mesh should be as tight as possible with no binding if that makes any sense to you. You should be able to spin the spur gear and it should spin for a bit with no binding when it's meshed up the right way. It's hard to mesh a T-maxx beacuse it's hard to see how much gear is grabbing the spur. It's all done by feel and if it makes sense.