JJSCUTLASS

OK 72 Cutlass Supreme, this wire is running down to my TH350 trans and it has no place to go
There are no electrial connections on my tranny , but are there supposed to be ?? It looks like it was hooked up before because the connecter housing is clean like it was connected.Wire is real long and comes out of Firewall wire block so it has to go to tranny or does it?? Car was disassembled for Resto
and nothing was changed or added so it has to go somewhere.I am sure somebody here will know what it is Thanks!!!

Texas69

My guess is a Kick-down lead for a TH400. Don't think it is used on the Th350's.

Octania

'72 had that electro vacuum thermal switch on the intake, and one of its wires had to go to the trans. I am not sure how a TH350 did that, but the TH400 had a connector for kickdown so they added a 2nd wire for the Trans Controlled Spark wire.

I see one wire there, so either it's a TH400 kickdown wire or a TH350 TCS wire. If the trans is not 1971-2 issue, it may not have a connector for said function. The TCS is, as I understand it, a smog reduction scheme that you can basically do without as long as you set your timing right and have the vacuum advance properly hooked up. This may require the use of the earlier non-electrical Thermal Vacuum Switch in the intake.

Read up on the system in the Chassis Service Manuals, and then you can decide how to arrange your engine's distributor vacuum, and what to do with the extra wire.

joe_padavano

Yes. Note how the connector body has two slots in a "T" shape. The bottom leg of the "T" is the TH400 kickdown wire. The top of the "T" is the TCS wire. On TH400s, both terminals were populated (as were TH350 harnesses in prior year). I'm actually a little surprised that the 72 harness only has the TCS wire, but the assembly manual drawing confirms "35M38" only, which is A-body TH350 cars. If your trans does not have a connector, it's been replaced with an older case. All this means is that your TCS isn't working, so bypass it if it hasn't been already.

JJSCUTLASS

I have owned the car for the last 17 years, there is no place to plug this wire into on my trans which is a TH350.This is why i'm confused!Where did it all of a sudden come from? Maybe it was tucked up somewhere and never used?? I dunno,only tranny work i had done was have it rebuilt,so it should be original from car.Car has always ran top notch no timing issues. I'm confused LOL!!

JJSCUTLASS

Maybe the tranny shop never rebuilt my exact tranny and put a Older One(differant case) in that was already re-built It is a 1972 tranny i believe though???

Oh,Thanks Joe and Octania for your input, i have a feeling i will not be using this wire

joe_padavano

Which means that you did not own it from 1972-1997. A lot can happen in that time, including replacement of the transmission. Look for the VIN derivative on the trans case. That will tell you if it's the original case or not. The wire was likely stuffed or taped somewhere and just fell down recently.

Sampson

Thanks for posting this! I am tying up loose ends on my resto and I have the same issue. I could not find where this wire went. My car is 72 but the trans is not original thus no place for the wire to go. Thanks Joe and Chris for the
info

JJSCUTLASS

Is this a stamped #?? I took a picture of the only thing i could find # wise and it was down along the Tranny pan flange> it was barely readable even after cleaning. Is this the VIN Derivative # i am looking for.

I can't believe some of the changes done to this car in the period i didn't own it which would be 17 years! I mistated in my prior post, so I have owned the car since 1989.

Guy working on my resto keeps asking me all these questions about this and that,things changed,colors he has found underneath while doing body work, why is this like that,who painted this and i keep saying "I didn't do it,I didn't do it"

MDchanic

The edge of the transmission pan flange is the right place, generally on the driver's side, but that's not the right number.

You're looking for a number like 32M123456.

- Eric

Octania

Huh
I see 32M150648 - maybe

Very light/ absent "M1"

Joe P.:
I would love to meet you someday.

MDchanic

Is 150648 the last six digits of your VIN?

- Eric

joe_padavano

What, long distance for the last few decades hasn't been good enough for you?

Work permitting, I'm hoping to get to the Nationals this year. Any chance you'll be down?

Koda

TCS can be bypassed like the gurus have said. From what I understand, the system consists of a vacuum solenoid with an inlet line and an outlet line. Electrical going in is from the transmission and there should be a temperature sender in the right side head. The left head has your gauge/light sender.

Idea is that vacuum advance is locked out for the lower gears and at low temperature. You get it in third gear when the engine is warmed up. I guess it's either for emissions or for being more forgiving with the timing for knocking (although you're more likely to ping in high gear low rpm applications.)

joe_padavano

It's for emissions, specifically to reduce NOx emissions (this was before EGR). There is no other reason to disable the vac advance, as doing this reduces fuel economy at low speeds. The thermal part of the switch is there to bypass the ported vacuum and run straight manifold vacuum if the engine starts to overheat. This is one reason why I simply bypass any ported vacuum use and run my distributor directly off of manifold vacuum (adjusting the initial timing as required).

JJSCUTLASS

Well it looks like the Original Tranny cause those are my #'s on the VIN
I really didn't think it would be the original but it is, which is Great and i am surprised!!

! So this wire has been hanging out for 40 plus years with no place to call home

At this point all i want to know is there constant voltage to this wire
when the car is running, cause i might have a purpose for it? To give it
something to do other than Hanging Out

MDchanic

No. That wire connects to one terminal of the TCS solenoid. The other terminal is connected to the IGN circuit, so that when the terminal in the transmission is grounded, the circuit is completed, and the solenoid pulls in, switching the vacuum to the desired source.

If you wanted to, you could jump the two terminals of the plug that goes to the TCS solenoid, to provide a (+)IGN line to the end of the wire, but that seems a bit jerry-rigged to me.

- Eric

JJSCUTLASS

Thanks for all the help guys!

I guess i am wondering now why is that wire there if i don't
have a TCS solenoid on my tranny ??? Assembly manual shows
the proper place for the wire to go,but why was the TCS eliminated on mine
from the factory??