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I am installing a later model 700r4 in a car with no transmission wiring harness (SBC350/Edelbrock carb). This trans has the 4pin connector and "rainbow" on the passenger side of the case near cooling line ports. Attached are pics of the valve body with pan off. If I want lockup in 4th, based on my wiring you see in the attached pictures, can I simply following the instructions in this video? I would likely add a 10A fuse and toggle switch from the 12V keyed source so I can turn it off as well.
Just simply do it like I Posted in the Thread currently next to yours:
Originally Posted by vorteciroc
Depending on the Model-Year of the THM700-R4...
(use an Internal or External Pressure switch).
Use a normally open 4th-Gear Pressure switch that provides 12v+ to the TCC Solenoid.
Run that 12v+ wire through a Brake-Pedal switch that will open the 12v+ Circuit when the Brake-Pedal is applied.
Last for the Negative 12v/ Ground Circuit for the TCC Solenoid...
Run this through an adjustable Vacuum Switch.
The switch should open the circuit if the Vacuum drops low (like when you accelerate quickly) so the TC UnLocks when you want to accelerate.
The TC will also UnLock if you press the Brake-Pedal.
The TC will also UnLock if the transmission downshifts below 4th-Gear.
This is how I set up all my Street Driven THM700-R4 Customer's Cars.
So based on my pictures, will I need to change out my existing 4th gear pressure switch? It appears to be a one-wire so I assume that is just providing a ground signal when “closed”? I assume I also need to change out my solenoid because it also appears to be a one-wire?
If the answer is yes to both, is it easier to just buy a kit? If so, which kit has all the parts I need to wire as you have recommended?
EDIT: my solenoid is a two-wire
Last edited by ericj205; May 16, 2023 at 10:21 PM.
Reason: realized i made an error...
when using a 700R4/4L60 from a computer controlled application (what yours appears to be from) supply 12V to terminal A (usually 12V from the brake switch) and connect terminals B & D together. confirm your 4th gear switch is normally open, set your meter to ohms and touch one lead to the terminal and the other lead to the metal body. if no continuity (OL) then switch is NO.
