Hi
I have an interesting one here,
Impala with 6.0lt and 4L80e conversion done here in Australia, Car came to me with the 4L80e in it but TCM and harness was 4L65. (It was simply stuck in 3rd gear)
I've changed the TCM and harness to suit (File attached) I've also changed the internal harness mainly because of and oil leak at the main connector. I also tested the TFP switch while the pan was off.
Now I can command any gear and TCC thru scanner up and down gears but when driven it shifts 1-2 and then 2-3 OK and at approx the right speeds but then it stays stuck in 3rd and will only change if I force it with scanner.
I'm not an expert on transmission stuff but definately not a noob either.
I need some help or pointers to see what im missing. I really want this car out of my shed.
Regards Ash
Wiring + Tuning Solutions