[McDeuce]

I purchased a rebuilt 700r4 from an individual yesterday that has 0 miles on a 2 year old rebuild. I have not been able to contact the shop that rebuilt it yet, and I'm hoping someone on here can help me identify some items.

1. The casting number is 8663549 (I believe this means it was built in 1988).
2. The code JDBA2050 is stamped on top.
3. The code 7MLM13911 (or instead of 11 it might be H) is on the side near the pan.

The person I bought it from said it had a shift kit installed for firmer shifts, and had been converted from a computer controlled torque converter lock up. Converted to what kind of lock up control he was not sure.

I took off the pan off, and I think he was honest about the 0 mile on rebuild statement. I snapped some photos of the wiring in the pan location that I believe is for controlling the lock up process. Most of them appear to terminate at a 4 pin connecter on the driver's side (3 pins have wires, red, black and blue). There is also a blue wire in there. I'll try to attach the photos in here.

Can anyone tell me what kind of lock up control I have by the photos? I can snap some more photos if anyone has questions that will help identify the parts I have.

The guys at bow tie overdrives (700r4.com) seem to know their stuff and I'm thinking of buying the necessary accessories from them. Any good / bad experiences?

[McDeuce]

What, I've stumped EVERYBODY?

Here is my guess as to what does what after some preliminary research. I could be wrong, so don't take this as the final word. I'll post my findings once I get expert advice.

There are three wires at the plug on the exterior of the case on the driver's side, red, black and white. There is one blue wire inside the pan as well. My guess is:

1. Red wire = 12v constant power from a fused wire.
2. Black wire = ground
3. White wire = connect to brake light circuit (activation and 12v will disconnect lock up).
4. Blue wire = tells lock up system that tranny is in 4th gear.

Just a guess. I'll let you know what I find out.

[OddRodder]

I don't know about the white wire, but the others are correct. I have actually hooked the lockup to a dash mounted toggle switch on an early pickup that I converted. Then when driving on the highway, a flick of the switch, and the converter locks up. This only realy requires the red and black wires to complete the circuit!

[willys36@aol.com]

I have an '85 200R4 that is similar to the 7004R but it only has a single pressure switch for lockup. Check with the BowTie buys. They are the greatest. I use them for all my O.D. tranny parts/troubles.

[troy-curt]

We have a member here that can tell you what you want to know.
Contact Crosley, he knows his stuff on the 700s.

Troy

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[McDeuce]

Thanks guys.

I talked to Steve at Bowtie. He suggested that instead of spending time trying to figure it out (he says there are 16 possible wiring combinations), to just replace the wiring in the case to match up with a known exterior wiring scheme.

In short (no electrical pun intended), buy one complete system. Bowtie has the complete system for about $80, forty of which is the in-case wiring.

I guess that makes the most sense.

Ever notice how you'll nickle and dime the smallest things, but then not nickle and dime the bigger ticket things? Why is that?

I guess it is because there are SO MANY of the little things, and they quickly add up to thousands!

Since I'm going to be buying multiple items (TV cable, inspection cover, lock wiring, dipstick), maybe he'll make me a deal.

I'll try Crosley first, though. Thanks again.

[Crosley]

the wire harness is an aftermarket unit from Rostra.

red is power
black is ground

The blue does tell the computer the tranny is in OD.

The white is part of the over-heat switch which is the round sensor there.

IF the tranny gets tooo hot the thermal switch locks the converter up to kool things off if the parameters are met.

The casting number means nothing to date of manufacture. The stamped number at the pan rail indicates it is a 1987 unit.

Back to your OEM question; this is a STOCK wire setup , NOTHING custom.

If you want lock up in OD only..... run 12 volts to the "A" location on the square case connector... the front , outside hole is "A"

Then run a loop of wire between the other 2 holes with metal connectors in them.. the tranny will lock up in OD every time the tranny shifts to OD.

[McDeuce]

Thanks Crosley!

Sounds simple enough.

One question though: if I connect the two remaining connectors on the clip (the white and the black), I'm basically powering the white wire with what used to be the ground wire, correct?

The current is going to flow through the red to the first connector, then through the black#1 to the second connector, through black#2 back to the clip, then through my loop back down the white wire.

If the above is correct, how is the circuit grounded and complete?

Thanks again for your time.

[Crosley]

Originally posted by McDeuce

If the above is correct, how is the circuit grounded and complete?

Thanks again for your time.

======== the switch is a normally open , self grounding unit.

that is where the ground comes from

[McDeuce]

I get it.

So it looks like getting the brake light relay external wiring kit from Bowtie will power it fine and safely unlock it in an emergency situation.

I'll just modify the connector clip with the loop Crosley suggested and be good to go. For that matter, couldn't I solder them together inside the case and not worry about messing with the plastic clip?

[orangef4]

If you are working on an older GM product with cruise control, here's something to consider. While working on my truck (1980 C10) I found that the brake switch was the same one used in the kit from Bowtie Overdrives. It's the same as every other GM switch I've messed with, but has extra contacts on the end that are normally closed, but open when the brake pedal is depressed. Also, a simpler way of wiring the lockup solenoid (the red and black wires), is to just run the black wire from the solendoid to the switch where the blue wire is connected now, and run 12 volts to the pin with the red wire. As Crosley said, when the tranny shifts to OD, the torque converter locks up.

[McDeuce]

Thanks everybody. I think I finally get it. I'm a real novice at electrical systems, but I think I get it. The way my tranny is wired (as shown in the photos):

The 4th gear switch and temperature sensor are both self grounding units. Current flows through the red wire to the solenoid. From there, current flows through the black wire to the heat sensor, then to the 4th gear switch. The ground is provided when either the over-heat switch or the 4th gear switch is activated, thus completing the circuit.

If I didn't connect the black and white wires at the exterior clip, the circuit would remain open even if the switches were closed.

The only remaining question is what do the white wire and the black wire that go from the temp sensor back to the exterior clip DO? Did they send a signal or current somewhere else on the car when the tranny overheated?

Orangef4, if I followed your suggestion, I'd simply be bypassing the over heat switch, correct? Wouldn't it make more sense to keep it connected?

Thank you all for your patience and time!

[willys36@aol.com]

Crosley; What is the pressure switch between the two that has no wires attached?

[Crosley]

that is a switch used to tell the computer when the trany is a lower gear and the TV pressure raises to down shift the tranny.


The dark switches are normally closed.

With pressure applied the switch opens.

I would remove any unused switch since they can leak.

The little flat filter support spring can be removed too. the redesigned filter does not use that

Originally posted by willys36@aol.com
Crosley; What is the pressure switch between the two that has no wires attached?

[willys36@aol.com]

There is the shiny silver hex switch on the left and the shiny (4th gear indicator?) and a shiny silver round switch on the right (temperature?). Then there is a grungy brown hex switch between those two with two brass electrical terminals with nothing connected to it. Is that a second thermal switch? Looks to be a pressure switch.