tvago, thanks. I think your truck has a separate trans control module, correct? I don't know a lot about it, but if I'm reading the diagrams right, my truck is an all-in-one setup. I was wondering if I could wire in a "dummy" solenoid to the truck's inputs, and then wire the TCC solenoid to ground. But even that wouldn't work all the time, as the same solenoid used for TC lock also shuttles for reverse and first. (Can't quite follow that logic, but okay). Maybe if I tap the right wires to show when the tranny hits 2nd, I could use that to trigger a relay to ground the solenoid...
Or, I'll just give up and go find a 5- or 6-speed for the truck. :idea:
[edit] found a link with some items that will do the trick, and then some:
http://www.powertraincontrolsolution...oduct/TCM2000/
Sigh, like most other things, they aren't cheap. $750 for a controller, $190 for a harness. I can buy a rebuilt 5-speed nv3500 for $800.