I wired up a manual switch to my 700r4 for tcc lock up. Has been saving me quite a bit of gas on the interstate and I even throw it on when cruising @ 40+mph with no stops expected...and can tell a huge difference in gas mileage. Anyone else experienced the same?

 

That is it's intended purpose
When the computer was operating it automatically , it lalso locked up the convertor in the lower gears to save fuel ( and reduce emissions )

 

When I had my third '78 'maro, I had the Painless Wiring lockup kit, a mild carbureted 350, a 3.08:1 axle and 235/60R15s. Lockup was fine as low as 30 MPH in OD, just 830 RPM. ( Later drove a 5-speed, non-turbo second-gen Eclipse 2.0L that could also cruise at 830 @ 30! ) I went to take it on a road trip. The centrifugal advance, I later discovered, not working when I was checking my MPG. Even so, 25.1 MPG at 65 MPH. I fixed the dizzy, but sold the car before I could re-check the MPG, but I know it would have improved to at least 26. Theoretically, put that in my '84 T/A, the aero alone should improve that to at least 27 MPG.

 

Well how about that! I was unaware. Guess I have never noticed.