TH700R4 Experts, Please Step In

[Scottie-GNZ]

Folks, I need someone who is intimately familiar with TH700R4s to help me identify internal components.

 

Background

I have TH700R4 ('84, so I have been told) and I want to use a megasquirt II to lock the converter automatically in 4th during normal driving and at WOT in 3rd at a specific RPM. The tranny was built quite a while back with a performance VB (Transgo, I think) but was rebuilt again about 4yrs ago. I do not have much details on the builds.

 

All the documentation I have read says TH700s have 3 wires at the connector for the TCC solenoid and the 4th gear pressure switch. However, this tranny has 4 wires. I just dropped the pan and was surprised to see what I believe are 2 pressure switches as can be seen in the pic. The 4 wires are compreised of 12V and GND for the TCC solenoid and seperate wire for each pressure switch. Since the stock tranny never had a 3rd gear pressure, I am assuming this VB was modified for one. I need someone to confirm this for me and let me know which is which. Cannot imagine the 2nd pressure switch being used for anything but 3rd gear. If I am correct, this will make it a breeze to do what I am planning.

 

Sorry for the crappy cell phone pic, but hopefully someone can recognize the ports those switches are on.

 

[231Z]

Scottie,

 

If you didn't get an answer to this yet, try Bruce Toelle of Performance Transmissions in the Sacramento, CA area. He is WE4 on turbobuick.com forum and moderates the Transmission section on that site. You might already know who this is because he is the originator of billet parts for the 200r4 BRF . He also has his own website.

 

Good luck,

 

Tyson

[Scottie-GNZ]

Yup, I know who Bruce is. Got several answers (guesses?) on this so I decided to wait until I get the car running again and connect a bulb to each of the switch outputs and see when the bulbs light up. Only way to know for sure.