How to test torque converter lockup solenoid

[codfish]

Can I hook up a 12 volt source to the 4 pin connector on my 700r4 to see if the lockup solenoid is functioning?

If so which of the pins in the connector is 12 volt in? Looks like only 3 of the 4 pins are/were used. I don’t have the wiring going to the trans so I’ll just use the pins in the connector on the trans.

Thanks
Gary

 

[Matt69olds]

If the pan is off, it’s easy to see what wires do what. I don’t know if you could hear the solenoid click with the pan on. You might be able to feel it by touching it while applying power.

It’s easy to test it hydraulically. Remove the 2 10mm bolts that holds it to the case. Put a blow gun on the end of the solenoid, blow some air in it. The air should vent. Next, apply power to the solenoid. Blow air in it, the solenoid should seal off the the air.

I’m sure there is a resistance spec somewhere.

 

[71RAT]

If the pan is off, it’s easy to see what wires do what. I don’t know if you could hear the solenoid click with the pan on. You might be able to feel it by touching it while applying power.

It’s easy to test it hydraulically. Remove the 2 10mm bolts that holds it to the case. Put a blow gun on the end of the solenoid, blow some air in it. The air should vent. Next, apply power to the solenoid. Blow air in it, the solenoid should seal off the the air.

I’m sure there is a resistance spec somewhere.

Low to mid 20's OHMs

 

[RanchWelder]

It's got 1 wire to the brake switch, 1 to the ECM for 12v and one for the ground...
You are correct, only three wires are used.
There's a bunch of info on converting it to a switch on the dash for 3-4 or just 4th...
The computer uses VSS to set it, so if you unplugged crap under the dash, you had better plug it back in with a quickness...

The brake switch or the neutral safety switch, shorts to ground when you hit the brakes, and releases the lock, or it's supposed to anyways. Mine burned up becuse it would not relese

I asked my builder to eliminate the lock-up, so it cannot short out underwater or get stuck because of TV settings. No electronics whatsoever, The connector now does nothing. No wires. No servo's no switches.

Just had to install a non locking converter...

Was just told by an expert builder, there's an o-ring which can be removed from the valve body piston, which allows you to run without a lockup... You'll have to talk to a transmission expert for instructions on the mod, so your exact model get's fixed correctly.

If you can afford the ASTG manuals, you'll be able to speak to an expert with a clue...

Make certain your wiring is not shorted and the servo's and electronics are not stuck, and TV is adjusted immediately, or you'll be without a truck with a burned up trans very fast. It's what happened to me...

 

[Matt69olds]

Technically, you need a non lockup valve installed in the pump to maintain the correct amount of fluid to the cooler. If you study the hydraulic circuit, the lockup valve restricts the amount of oil that goes to the oil cooler. Since probably 85% of the heat generated in a transmission comes from the converter slip, keeping the same cooler flow with the converter locked could possibly result in over-cooling.

The converter clutch solenoid gets power from the brake switch. Press the brake, the switch opens, the solenoid loses power. The ECM supplies the ground. The ECM looks at vehicle speed, engine coolant temp, throttle position, vacuum reading, what gear the transmission is in, plus a few other things to decide when to ground the solenoid.

 

[codfish]

Thanks for the advice and replies.

My transmission is still sitting on the garage floor waiting for me to get back home from work so I can get it to the guy who is going to rebuild it for me. I work away for 2 weeks at a time. A few new parts I have ordered have trickled in for it.

I feel I should maybe give a better description of what I am working with.

Truck is registered as an 84. It is a Franken truck, as different years were used by a previous owner to build it.

There is no ECM, no cruise control switches , no wiring for lockup torque converter, etc.

The 700r4 transmission is a 92 as far as I can tell from the hard to read numbers on the case, and lack of “pressure ports” on the side. K case.

New 4 pin plug in has arrived, new TCI tv cable and bracket, and solenoids and switch.

Gary

 

[RanchWelder]

Listen to Matt69Olds...
Delete it, NO Lock UP, problem solved forever... Non lockup valve... FTW
Buy a non locking converter and move on...

The comments in this post are NOT made to infuriate transmission builders or steal money from their families...
Please do your own research before deleting any lock up on a 700R4...