Tranny Problems

[cortster]

Hello tranny techs. New to the site so be patient.

Question on 1998 4t60e that I just rebuilt.

On my first interstate driving after rebuild, it would not remain in overdrive, erractically switching between 3rd and overdrive (mostly staying on 3rd). When stopping, it would downshift into 2nd gear and after coming to a full stop and attempting to take of again, she would attempt to take off on 2nd gear and then abrubtly downshift into 1st.

I was originally getting a series of codes, some associated to the EVAP system and others that were most likely associated to the tranny but once I repaired the EVAP system codes none of the codes have returned. I don't know if the EVAP codes were influencing the tranny codes or that I have not driven the vehicle on the interstate long enough for PCM to pick up the malfunctions. However, although no codes have appeared, I can still feel the symptoms described.

Feedback will be appreciated.