starter keeps breaking!
 

alright guys about a week ago my jeep kept not starting and i hit the starter with a hammer and it worked i got tired of hitting it and my friend gave me one out of his cherokee that worked fine. so i put that one in and it was fine for a few days and now its acting up again and i had to hit it again today in the mud!! is there something that can be shorting it out again? i wheel it all the time and this just starting happening. also today it stalled in the mud and the distributor is sealed with rtv and my intake is higher than stock with a cone filter. when i tapped the starter in the mud it started up fine but i don't know why my jeep is acting up help please thanks guys.

sounds like a wiring problem to me. make sure connections are tight and are not shorting