Hi, well I'm just about done doing DIY build of 700R4. I'm thinking about semi manual control of TCC instead of the 1227747 ecm controlling lockup. I will have more control of it offroad. Please take a look at this circuit and see if I'm missing anything. Im about to close up the pan so any input please? I'm using a N.O brake switch and a vac switch as primary control. See any issues with this wiring? Should I add a switch to only operate in drive?

 

Why go through all that complicated work when you can buy a lock-up kit from Monster Transmission for $100 ?...

 

Thanks for the input. I did look at the kit, it seemed a bit too manual. My wife will drive this as well once in awhile. But looking at this drawing again, maybe it's to much. Maybe I should wire ecm to do it instead? I was just trying to avoid buying a speed signal convertor so ecm knows speed. Then possibly needing to tune some to operate. That speed signal convertor is 100 bucks or so. It used to have one from dakota digital, but it broke. So cost is pretty much same either direction.

I could also eliminate manual control and the time delay. Don't really need those. If the brake was a NC I wouldn't need the relay either.

 

I don't know what year700R-4 you have, but mine is the older version that has 2 external oil pressure ports (2nd & 4th). Installation of the lock-up kit I got was super easy.
An external oil pressure switch threaded into the 4th gear port completes the circuit sending 12v+ to the connector that the ECM originally plugged into.
I pulled the 12v+ from the brake switch, so it is instantly interrupted when the brake pedal is pressed. An illuminated rocker switch was also included for manual override of the TCC, but I did not install it since I don't feel a need for that function. Monster also offers an internal system for the later model 700R-4 if that's what you have...

 

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.

 

Thank you both. It's a 1992 model 700r4 with a type 2 VB. It has one threased hole inside for 4th switch only. I perfer internal lockup componets due to offroad application.
I can wire more like those examples above. I have a single stud 4th switch though. But my vehicals brake switch is also N/O circuit, press brake completes circuit.
I'm just going to omit the second manual tcc control switch for low gears operation and also remove the time delay. Thanks.

 

Have you seen this video?...

 

I have now. Yeah that's a simple way of doing it. Makes sense when you hit brakes enough, it will come out of 4th and unlock. Thanks.

With the 4th switch this should never happen. But, let's say the tcc remained locked but the trans shifted gears like 4-3 downshift, what happens to my fresh rebuilt trans? Lol cause I have no idea.....

 

Should lock up only in 4th. Hit the brake; it unlocks whether it down-shifts or not...

 

Honestly, The Post above is very Cheap and Easy to do.

I would consider doing anything else unhealthy for the Transmission (unless the Torque-Convverter is very loose) and a waste of Money and time.

 

Yeah, I wasn't suggesting to do or not do what it shown in that video. I just thought it was interesting...

 

Thank you both. I'm going to do it using just the brake sw, vacuum and 4th pressure switch for now. Well and the relay since i have only a N.O brake switch. But No toggles or timers for now. Eventually I'll wire it into the ecm when I got nothing else to do and feel like buying that speed signal converter. Then I can mess with that if I feel the need.
Took tomorrow off of work. Trying to get the transmission back in the jeep. But spent tonight making new brackets for the t-case shifter.

I feel pretty confident in the rebuild but anything could happen. I just want it back in so I know it works. Lol. Also ran all new trans lines and added a cooler. Hoping I can now drive it and not worry about the trans baking itself. The idea with the manual control of TCC was offroad situation I could lock it up in any gear so it could cool down. But again I still don't really know how bad it gets if it shifted gears? So that's getting left out. Should stay cooler and now I have temp guages to watch the trans temp too.

 

We can discuss additional wiring for Lock-up via Toggle-Switch (Lock-Up Override/ Manual Control of Lock-Up).
This would be done in addition to the Wiring that I already Posted.

Note: There is NO way to Lock the Torque-Converter in Low-Gear/ 1st-Gear.
ONLY 2nd, 3rd, and 4th Gears allow for the Torque-Converter to be Locked.

WARNING!!!
There should never be any Shifting done while the Torque-Converter is Locked.
Forcing this to occur, can cause Violent and Catastrophic Failure of the Transmission/ Physical-Explosion of the Transmission.

I have seen this occur, and some of the Gear-Train of the THM700-R4 can come through the Floor/ Body of the Car and into your Legs/ Body!

 

That's a bad day. So I'm definatly not interested in manual TCC control outside 4th.
Do the 4th pressure switches ever fail closed? If so, I will add the external one, in series for redundancy. I never want to pull this trans out again. Lol.

 

Really? You can't down-shift from Overdrive to third without causing damage? I do it all the time in my Honda (obviously not a 700R-4)...

 

It depends on many factors:

-Vehicle Weight.
-Gearing.
-Engine RPM.
-Line Presssure.
-HP.
-Diameter of Torque-Converter.

A 200 HP, 2,800Lb Car with low Line-Pressure, a Small Torque-Converter, and Gearing that is not aggressive, while at low Engine RPM can get away with it.