I rebuilt a ford transmission and I have the code po731

Question

Runs good if I stay in a stop light for more than 3 minutes it feels like first gear Not engaging and kicks but only if I stay more than 3 minutes

Answer 1

P0731 First gear error

This is no first gear, This type of transmission is not a easy rebuild no matter the  experience , it a tough one. This is obviuos a internal leak, It always a good option of having a new fluid pump rather than rebuilt.