I have a 95 4l60e from a camaro that Im trying to use with a 94 lt1 engine harness and computer. The 95 has one extra pin on the connector and I cant figure out what its used for? Any info about what this extra pin is for (pin U) or how I can make the trans work with my engine would be greatly appreciated.

 

The extra pin (pin U) is for the PWM lockup solenoid that was used in the 95 and later 4L60E. Used in conjunction with the regular lockup solenoid, it's supposed to soften up the hit of the lockup by bringing it on gradually.

I know the PWM lockup system can be eliminated so the TC can lockup up instantly like normal, but I'm not exactly sure how it's done. Once thats done, you will still be able to plug in the '94 harness and ECM with your '95 tranny since pin U is not needed, and will be absent on the harness.