looks like your motor plate got loose a little bit and contacted your slipper. locktite is a must on trans screws because they only grab 3-4 threads in the motor plate.

Clicking is usually either the gears in the gear diff, or the idler gear in the transmission. Looks like yours is the RTR model...and both of those are suspect in the RTR. I would double check those items again. Idler gears can "look" ok, but clean it off real good and look at it real close to see if it's chewed up.