I had my transmission rebuilt last week and it's been running perfect...even better than when I bought the car. I was driving today and passed a slower vehicle. The car shifted into a lower gear as I pressed the gas, however it never shifted back into overdrive! I now only have 3rd gear. When I stop at a stop sign or light it won't shift down to second then first. Thus when I start up again I'm literally going from a complete stop in 3rd gear. I noticed the SES light came on and it's throwing this code:

"P0785 Shift/Timing Solenoid Malfunction"

Is this something I can fix myself or should I send it back to the place that rebuilt it and let them deal with it? I also want to know what happened so that if I do take it back I have an idea of what to expect. Any help is greatly appreciated.

 

P0785 is 3-2 shift solenoid circuit electrical. Take it back and have the shop fix it.

 

Thank you! Dropped it off this morning.