I actually have the Snap-on tool that will measure that thing, but I never mess with it. I just put it on, and rotate it back and forth till it shifts decent. Too far one way will shift at too low an RPM (hard early shifts, like firstimediesel's). Too far the other way means it revs higher before shifts. This also tends to make shifts that are a little on the firm side, and it holds gears longer. It would be great for towing.. Somewhere in the middle is where you ought to be.
If you are waaay off, the O/D light will flash on the gear lever. Also, the plug that goes on the TPS can some times be faulty, and all the adjustment in the world will not do it. I had that problem with mine. I had it adjusted to factory spec, and it would work 5 minutes and start flashing the O/D light again (with horrible shifts). I thought the bracket was bent or something, so I started fiddling with it manually. I got to a point where it seemed to be staying constant, but a little off, so that was good enough. Then a day later it went out again. I finally found that if you wiggle the wire, the light would go out. I replaced the plug with one off a junker, although I have now found a place to get new plugs from (Auto Parts Fast at RockAuto
). I replaced the plug, but never got around to readjusting the sensor to factory spec. It works well enough, and at the time, I didn't have the Snap-on scope tool. Now I have it, and I'm too lazy.