I've got an 1880 kv hobbywing combo with the xerun 80a ESC and 20C 5000 Mah Lipos at 14.8 V. After the third run it started emitting a terrible screeching sound. Plus It doesn't want to reverse. Can anyone tell me what has happened? I've ordered twin 11.1v lipos and a Castle Creations Monster 2200kv combo system. I want to sell the Hobbywing system but I need to know if its burned out first. Any Ideas?

It could be a multitude of things. Considering it's that HobbyWing stuff, I'd assume the motor gave out. Have you determined if the noise is actually coming from the motor? If it is the motor, a bearing may have gone bad. There isn't much to those motors, so there's very little that can go wrong mechanically.

I'll check everything and report my findings back