I got a 1983 6.2 diesel and im boggled. I found a square four prong plug under the driver side of the truck. Im assuming this is lock-up control for tc? I want to put a 700r4 back in the truck for compatbility. How is lock-up in the tc controled? Is it a special 700r4 that goes in the truck? Someone help please

 

That truck came with a 400 turbo not a 700R4 my guess is that is the electric kick down for it, look at the PRND21 if so it was the 400 turbo if it is OD 321 that's 700R4.

And the 700R4 didn't have a lockup torque converter overdrive was controlled by a Detent cable.

 

This is a k10. Th400's only came in the k20's.

 

All so i looked today my shifter says PRND21. So im guessing a 700r4 is not what came in it

 

You can believe me or not but in 1983 the 6.2 only had a turbo 400 behind it as a automatic trans mission and manual transmissions have the NV3500.

I have owned a few of these trucks and the only thing they changed up on these transmissions was civilian vehicles had the electronic shift modulators and the military trucks M1008's and M1009's and so on had vacuum shift modulators.

 

Then what is the random plug under my truck for?