as im sure you can see the it seems like the differential is broken........that part just snapped right off.....so im guessing i have to replace teh whole diff? is there like a better one i can buy, a hop up from the stock? and i might as well add gear oil when i put the new one in, so whats the best way to get rid of all the grease? will brake cleaner work? we use that for cleaning metal at the garage i used to work at.....thanks