TroyTroy

hey i bought a losi mini 18 baja a couple days ago . its had 3 batterys runs threw it. and on the last turn it all of a sudden it had a buzzing sound. so i took to the motor and all the diff apart. and the spur gear i think it is was making the noise. when i took it off there was no noise.would it just be a naer gear needed? and second problem is theres a sorta ticking sound sometimes in runtime. what may be causing that?
all surgestions and comments will be greatly appreciated.
Troy