So I have been having problems with my transmission in my 93 F-150. It would work normally part of the time, then the check engine light would come on and it would start shifting very rough, and a few miles down the road the light would go off and it would work normal again. Eventually my trans lost 1st gear and OD, but I assumed this was all because of the "simple minded" people my dad had replace my last trans when he burnt it up towing. So I ordered a professionally built trans and put it in myself. And it still has the problem that the last one did where it works normal sometimes, but sometimes the check engine light comes on and it shifts rough. So I hooked me scanner up to it and I pulled a DTC: 637 Transmission temperature circuit above maximum voltage. What exactally does that mean. Is my trans getting too hot, or do I have a bad sensor. I wouldnt imagine it is from the trans getting too hot, because it will do it sometimes right after I leave in the morning, and everything is still cold.

 

It was durring a KOEO test too if that maters

 

I don't know if that is because of a overheating transmission or electrical problem with the truck. Did you flush out the transmission cooler when changing the trans.

 

Yeah, I flushed the cooler lines