I'm having trouble setting the mph at which the TCC engages in my truck. It seems whenever I set either the high gear or the low gear mph it doesn't work. If I set both of them to where I want it it works. Anybody else have issues with this? What I am trying to do is get it so that the TCC can engage in 3rd gear but not engage in OD until a higher mph to avoid lugging the engine at like 40 mph in OD with the converter locked.
Forgot to add it's a 7747 ecm and 700r-4 trans.

 

I figured out what I was doing wrong. I hadn't upped the unlock mph in low gear. I did that and now it will turn the TCC off if it shifts into OD before my set mph. Not so much locking/unlocking of the TCC now.

 

In the Tuning Guide Book sticky, under the '8746/'8063/'7747 ECM chapter, is a write up on the GM TCC logic. It is a worthwhile read.

RBob.