Originally posted by Charlyg
Hi Richard - I suppose the finalOD gear in the 700R4 is a basic lockup! - ?maybe? - anyway thanks for the info - I've been told to expect no more than 12-15 inches of vacuum from this combo - does that mean I may have to use a booster? thanks again!
Charlyg
the stock 700r4 uses a lockup converter. it is locked via the engine computer. you can spend a small amount of money ($75 to $150) to buy a kit to eliminate the computer OR do this:

there are 3 wires on the trans plug - pin A (pink wire i think) got to ign hot (12+). the other two wire get tied together. there ya go. now to get fancier, you can get a delco switch that will unlock the converter when vac drops, but if you have only 12-15 in to start it may not ever lock up. You can also run the +12 wire through the brake light switch so that the circuit is broken when the brake pedal is pressed. I have not done that and have no problems - when i slow down, the trans downshifts and unlocks...simple easy!

Operation: one wire in the trans grounds when the trans is in 4th. the other one is the - lead to a solenoid. so when the trans goes into 4th, the converter will automatically lock up, and when it leaves 4th it unlocks.

if you do not lock it up, at 45+ mph in 4th you will see a temp rise of 30-50 degrees - the trans will overheat and die.