TCC wiring diagram needed

[Peer81]

Hello everybody,

I've replaced the TH350c from my 81 Corvette for a 700R4 from a 90 Corvette.

As my 81 has a ECM with TCC lockup control I'm looking for the wiring diagram from a C4 Torque converter to see if this is a plug and play or not.

My 81 has a normal 3 wire connector. Terminal A has constant 12v, B is the high gear input and D is the ECM ground (or in better words a constant 12v when braking or when the ECM doesn't agree with the lockup.) I was under the impression that A had a constant 12v with the brake switch disconnecting the 12v. So I changed the wiring inside the 700R4 to match that. As this isn't correct I want to see how the 700R4 is originally working and if this matches my 81 wiring. (So I can change the wiring back to original).

If somebody could help me that would be great.

Greetings Peter

 

[boomdriver]

Hello everybody,

I've replaced the TH350c from my 81 Corvette for a 700R4 from a 90 Corvette.

As my 81 has a ECM with TCC lockup control I'm looking for the wiring diagram from a C4 Torque converter to see if this is a plug and play or not.

My 81 has a normal 3 wire connector. Terminal A has constant 12v, B is the high gear input and D is the ECM ground (or in better words a constant 12v when braking or when the ECM doesn't agree with the lockup.) I was under the impression that A had a constant 12v with the brake switch disconnecting the 12v. So I changed the wiring inside the 700R4 to match that. As this isn't correct I want to see how the 700R4 is originally working and if this matches my 81 wiring. (So I can change the wiring back to original).

If somebody could help me that would be great.

Greetings Peter

I can find the elect drawing and post what I see late tonite or tomorrow. From what I know, its pretty straight forward. If its just plugs that change...some pigtails are available from better salvage yards. J&D Corvette, 20Th auto parts Phx...will have whatever part.

I'll look and let you know.

 

[Peer81]

I don't think the plugs changed but if they did, no problem I have the right tools to get them out and change them around.
If you can find the diagram and post it that would be great

My 81 shop manual has a trouble shooting page on the TCC, if yours has one to, that would also be very helpfull

Greetings Peter

 

[vetteoz]

D is the ECM ground (or in better words a constant 12v when braking or when the ECM doesn't agree with the lockup.)

D is the TCC control wire.When grounded by ECM lockup occurs.
Hitting the brakes cuts power to solenoid and disengages TCC
over-riding ECM

 

[Peer81]

Thank you for the picture!
It shown the brake switch is in the 12v cable (A) and the D cable is the ground controlled by the ECM. Not that it is a big or important difference but mine has the brake switch in the D cable along with the ECM controlling the ground. Or to explain better. The D cable also has 12v on it, exept when your driving faster the 40mph it grounds and when you hit the brakes the 12v is back (or in other words disconnecting the TCC solenoid).

I'm still wondering what the high gear feed does and what it's for...

Greetings Peter

 

[vetteoz]

I'm still wondering what the high gear feed does and what it's for...

In the tune there are different operating parameters for the TCC depending whether it is in high or low gears