Newly rebuilt 4l80e (700 miles) now won’t shift into 3rd gear

[NickTransmissions]

Weirdly enough no continuity difference with the old harness. Put a new rostra in today and the temps are lower than they’ve ever been before 150-170 (and it’s currently 98 here). Drives wonderful, shifts hard. I guess the harness was it.

The tale tell sign to me was the abnormal line temp yesterday; 45 degrees, then 140, then “error.”

So the prev harness' temp sensor was bad.

Did that harness that you just replaced look new or did it look like the original (or an original) harness?

 

[txaggie]

So the prev harness' temp sensor was bad.

Did that harness that you just replaced look new or did it look like the original (or an original) harness?

Hard to tell. It was clean but the wires were pretty hard and not easy to maneuver. Main connector looked clean.