metalmen

ok i am swaping a th350 with a th400 i am one of the purest who want it to look factory, the kick down wireing is it already in the car ,i have the pedal,switch, and bracket, does anyone know or have the wireing to the switch on the trans or know how the factory did it? any help would be great thanks

joe_padavano

Yes, the wiring is already in the car. There should be a two wire connector (orange and pink wires) taped up in the dash harness above the accelerator pedal that connects to the switch. A 1972 TH350 car should also have a two-wire pigtail running to the trans already (one dark green wire and one black with orange stripe) since these cars had transmission controlled spark and even the TH350 had an electrical connector (though only one of the two wires was used). The dark green was for the TCS, the black with orange stripe is for the TH400 kickdown. If your TH400 only has a single terminal connector on the case, that's fine but be sure the black/orange wire is the one connected to it. You'll want to bypass the TCS if you don't have the trans switch connected.

metalmen

ok the th400 i have has 2 prongs, do i still have to bypass the tcs? and how is that bypassed?

joe_padavano

Nope, just plug it in.

Now, TCS is an early form of emissions control that inhibits vacuum advance unless the trans is in high gear (third in the case of the TH400). Most folks simply bypass the system by running the vacuum hose from the distributor vacuum advance can directly to manifold vacuum (or ported vacuum if you prefer, but I don't want to start a manifold-vs-ported-vacuum discussion here).

Your system may have already been bypassed by a previous owner.

metalmen

thanks got it now i can sleep tonight

nj_cutlass72

I want to attempt this, if you guys have any pics that would be helpful. I recently had a TH400 installed but did not attach any wires to the tranny, so im wondering what connects to the tranny for kickdown, I would have to locate this wire and also there are wires that go between the pedal and harness? thanks!

nj_cutlass72

so I took a few pics of my cars set up, there are no wires to hook up near the top part of the pedal as far as I can see, also found the connector by the tranny and no wire near there as well. any suggestions?

ent72olds

Someone can correct me on this, but since your car had a TH350, it wasn't electric kickdown, now the TH400 is....harness may be different...?

ent72olds

Also, that spot on the pedal is for the cable....for the TH350...

Jimmy_B

I will also be attempting this in the Spring. Already purchased the kickdown switch and bracket from Scott (oldspackrat) here on the forum.

Thanks for the info on the wiring colors Joe !! I'm crossing my fingers that all the wiring is under the dash as you mentioned.

nj_cutlass72

sounds like I may have to rework a few things, whatever it takes would like to try it out.

ent72olds

Ooops! After reading Joe p's post, I guess it's up there somewhere....maybe get a wiring diagram...

Jimmy_B

True, however I've been told that you can simply grind that eyelet off the pedal linkage in order for it to function properly with the new switch. I hope this is correct, otherwise I'm going to ruin a perfectly good pedal assy (for a TH350).

nj_cutlass72

would you post the pictures for the kickdown switch, bracket and the wires. I wonder if Scott has a second set for sale.

ent72olds

Joe, you don't happen to see it laying around underhood near the brake dist block? Or maybe under the booster? That's where mine is....

ent72olds

The switch would be located under the dash at the pedal linkage. Go to wildaboutcarsonline.com In the '72 Olds Chassis Service Manual (CSM) in chassis electrical section...all the pics you want!

Jimmy_B

I will get you some pics tomorrow of what Scott sent me. Not sure if he has another set?? You should PM him that question...

nj_cutlass72

thanks!

Jimmy_B

Here is a picture of the bracket and switch.

metalmen

ok i got to work on the swap today found the under dash wireing up there, under the car i have only one black wire on the th350 , is there a wire under the boster? out of the fuse box to start the run to the trans, and what color, i spent a hour and didnt find any taped up factory wire under the hood, any idea? thanks

Greg Rogers

Wow this is great, I have been trying to figure out this mystery about the wiring on my car a while. I saw the svc manual shows the 2 prong connecter and the green wire comes from the tcs and goes to the transmission switch. But the tcs pressure switch I found only has 1 terminal. Now I see only the green wire hooks to the tcs switch and the blk/org wire isnt used on the t350, but on the t400 the same connecter goes to the combo tcs/kick down switch. Thanks for that info Joe. And metalman, on my 71 Cutlass the 2 wire connecter was not hooked to anything but was coiled up in a zip strip (surely done by a previous owner). Hopefully you can find it. Great stuff on this site!!!

metalmen

yea great people on here, and they know more than oldsmobile itself!

efinley

My third gear is slipping and need new transmission any suggestions conv. 72"

Octania

Yes!

IF you can R&R it, have your local small shop rebuild it during a slow time, should be cheap. Any TH350 should be readily available. If your trans is VIN stamped to match your car, it'd be wise to keep it in the car. The VIN stamp is just above the gasket, LH side, in the trans case textured aluminum. It will look like your VIN but with the 2nd thru 5th characters missing:
342672M101123 VIN would have a trans and engine stamp
32M101123; the characters are about 1/8" tall.

Start your own discussion thread rather than add into ["hijacking"] an existing one?

And, a nitpicking but easy to fix detail that will make your posts easier to read and digest...

(72") reads "seventy two inches" - put an apostrophe (') where the characters are missing for best presentation: to indicate a 1972 model convertible, use ( '72 convertible ).

Note that I used parentheses instead of quote marks above to avoid confusion with the apostrophe and quote mark otherwise employed.