Originally Posted by
Ranger6202
I understand your feeling on the quality of the harness and the reputation of his establishment. However, you still have a problem, and if you're like me, you're probably lying awake at night staring at the ceiling going through a random list wondering what the hell is wrong. For peace of mind, I would go double check the pins @ the tran connector and the ECM pins. Since it's custom, i don't know if he kept the OEM colors, but that would be the easiest method to verify they're right......or it might just be a loose pin. I've watched our multi-million dollar facility at work lose thousands per hour due to a measly loose wire that was otherwise perfect for years. Best case is everything is right and in the end it'll be checked off the list.
One other thing i came across in my self-made trans reference book was the change in 4l60's over the years. I don't think i caught what year 4l60 you have. If it's a 97 and newer, the pin out and electrical hardware is the same up to about ~2006? If its a '95 and older, there were 2-3 years where they changed the TCC and 3-2 solenoid hardware and control method back and forth. With that info and that you are having problems with 3rd gear and TCC, i am curios to what year your trans is. Or if it was recently built, what year of hardware was used.