On Sat, 28 Sep 2019 19:07:56 -0500
Terry Coombs wrote:

snip
Well , so far I have traced the brown/white wire across the steering
column to where it plugs in to a device - probably a relay of some kind
- mounted on the steering column . It comes out on a blue which goes
thru the firewall alone then to a small bundle that heads towards the
tranny . My guess is that the blue wire plugs (or is supposed to) into
the lockup solenoid , and is either unhooked or damaged and grounded .
I'll find out in the morning .

Mines an 1982 K10 4x4 with same tranny...

The wire goes to a switch on the brake pedal, out to a switch on the
throttle and then to the tranny. Stepping on the brake or not enough
throttle unlocks the torque converter clutch.

On my truck the torque can lock in second gear if all the above
conditions are met. i.e. enough throttle, no brake and going fast
enough. However if you are in 4x4 it will only lock in overdrive/4th
gear. I added a switch early on to make it think it was in 4x4 so it
will only lockup in overdrive while in 2 wheel drive.

This was in 1982, maybe they wised up and did my hack to all later on.
That 700R4 is not a real solid, heavy duty tranny. Never should have
been used in trucks...

--
Leon Fisk
Grand Rapids MI