Just got the transmission rebuilt in my truck and other then shifting hard sometimes it has been doing great, Hooked it up to the goose neck this evening and everything was fine then went to back it up and pull it forward and after a short distance the od light was flashing and when i ran a check on it it was p0720 any ideas? The transmission has less then 1000 miles on it?!?!?

 

Take it back to whoever built it and tell them to fix it. Is there any warranty with it?

 

it does have a 1 year warrenty, but i figured if it was a sensor i would replace it. I did have a goose neck hitch welded in today...Not sure if that helps or not.....Was just looking to see if anyone else has had this problem

 

It means there is no input from the output speed sensor.

Either the sensor is bad or the wiring to the sensor is bad.

 

After doing some looking around and talking to some people I found my. Battery wires were all lose I tightened up those and it has been good ever sense (the guy who installed the goose neck hitch in that day did not retighten the cables)

 

The best fix it a free fix, Glad you got it up and running