Well, now the CEL went off, and it seems to be working again...it has a slipping problem tho that's also random. It was used to pull something at one time, add they did install a trailer break system. The sound was almost like a metal that was bound up, then let go. It was loud, and in the either the trans, or xfr case. I'm not sure what it's issue is. When the light comes on again, I'll read the codes. Every time I've taken it to read codes, it's that trip that the light goes off...