700r4 wiring diagram

[Ratau]

I need help with the wiring diagram for the 700r4 transmission (9YTM179H out of a 1989 4.3 petrol model). This transmission was installed by the previous owner in my 1982 Chevrolet Blazer 6.2 diesel but the lockup did not worked. When I tested it, it showed a short circuit. I removed the oil pan and redo the wires, there are two pressure switches a two terminal and a one terminal both test normally close. Please explain how the switches get activated. What I understand is that certain diagrams uses a normally open switch in series with the solenoid ( N.O. oil path). How do I ID the converter to make sure it is suitable for the diesel?

[Animal]

These two web site should help out.

http://www.700r4.com/tech/tcc/

http://www.montecarloss.com/SSThunder/drivetrain.html

[Ratau]

I did the wiring as it is on the web-page. Keyed 12 volt supply trough the n.c. brake switch to the double terminal pressure switch (n.c.) inside the transmission to the positive side of the solenoid (n.o. for oil) to negative. I also installed the switch (for towing) to bypass the pressure switch. That was easy.

My question: If the pressure switch is n.c. it means the solenoid is activated as you turn the key to start the engine and that is identical to the bypass switch (for towing) in a on position.

What activates the pressure switch and when?

Is the pressure switch in your diagram n.o. or n.c.?

How will I know the lockup is activated?

Will the transmission become damage if the lockup is activated on a steep downhill (in other words use the engine to brake the vehicle). At this stage I downshift the transmission manually to 3rd or 2nd to slow down because if I take my foot off the accelerator the engine revs. drops to almost idle if going downhill.

[britannic]

Ratau: it's important to note, that over the years the way the lockup is activated was changed. Also, rebuilders have their favorite way of wiring the transmission to get the lock up and allow for manual control of lock up in the other gears.

On mine, I had to drop the pan and check what they had done before I could successfully wire it up.

Some years had more than one pressure switch, whilst others used only one. On my 700R4, a 12v power feed is connected to the TCC solenoid and the negative is connected to a single terminal (some switches are dual terminal) 4th gear pressure switch (N.O.). The pressure switch is grounded in the valve body, so as soon as the 4th gear circuit pressurizes, the switch closes, grounds the TCC solenoid locking it in (my tranny has a delay to allow 4th to fully engage and not jolt the drivetrain).

I also have another ground to the TCC solenoid that runs into a dash mounted switch, this allows me to manually lock the TCC in 2nd and 3rd for towing.

If you're not sure of the configuration for your model 700R4 (if it's not stock), then you could use a continuity or ohm meter to deduce whats going on and then wire accordingly.

The 700R4 Forum (http://bbs.netgearhead.net/postlist.php?Cat=&Board=700r4) at Netgearhead is awesome, here's the link: 700R4 Forum (http://bbs.netgearhead.net/postlist.php?Cat=&Board=700r4)

[Ratau]

Britannic
I believe I did the wiring the correct way. What worries me is the pressure switch that is n.c. Will it do harm if the solenoid stay on via the remote switch? What I understand is that it will lockup in 2nd 3rd and OD.

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