camron

hello everyone im just a new car guy and new to olds im used to chevy this isnt my car im doing this as a learning project its my teachers that doesnt no anything about cars im doing this in my high school auto class..ok the car is a 72 cutless with a 350 and no kick down cable what kinda trans is it a th350 or th400.i would like to know cause i need to change filter and gasket

rocketraider

This car should have a Turbo 350, but I have learned to never say never.

If the pan is rectangular with one corner cut off, it is a T350. If the pan looks vaguely like the Rio Grande side of Texas on one side, it is a 400. 400s have electrical kickdown switches with no downshift cable.

joe_padavano

Stock trans would have been a TH350. Most likely is that the cable is missing. Look at the trans pan. Square pan with one corner cut off is a TH350. Irregular pan that looks roughly like the state of Texas if you squint is a TH400. Note that an original 1972 TH350 WILL have an electrical connector, even though the trans uses a cable kickdown. These model years used transmission controlled spark as an early emissions system and the connector is part of that system.

Octania

6 bolts secure the tail housing to the TH400

4 bolts used on the 350

You sure you don't have a kickdown cable, located next to the throttle cable, on the firewall, leading to the pedal lever inside the car?

That's common on 70-72 or so Cutlasses.

camron

joe_padavano

That's what Chris said:

The 1969-72 A-body cars operated the cable directly off the accelerator pedal, not the carb. Look at the firewall and you'll see a second cable just below the accelerator cable.

camron

Ok thank you i was looking in the wrong spot for the cable...this has been my first older car and my normal auto teacher is gone this is my subs car and im only 18 the most kinda work ive done like this has been on my 91 chevy truck thanks for the help

rocketraider

Back to your vacuum question, the 350/375/400/425 transmissions use a vacuum modulator to control shift points. You'll see it on passenger side of the transmission- it's a round thing with a vacuum hose hooked to it and then to a steel line that goes to the intake manifold. Engine vacuum varies with throttle opening, so the vacuum modulator is an efficient way to control shifts.

If the hose comes off or the modulator fails, the transmission will still shift, just way late as the governor is controlling shift points then.

Keep asking- we'll help.

svnt442

Don't assume that because it was a 350 engine that it came with a 350 trans. I had a 72 Supreme that came with a TH400 behind a 350.
But if you found the cable on the pedal than you do have a TH350 for sure.

joe_padavano

Not from the factory. All the factory documentation shows the TH350 behind the A-body small blocks in 1972.

GAOldsman

I see Joe is right as usual Not even a W31 could be had with a TH400. But I see in '70 a small block Delta could be had with a TH400. It seems as if it should've been an option all the way across the board

joe_padavano

The TH400 (and actually the TH375) was used in the heavier cars. The only A-body I've ever seen with a TH400 factory installed behind a small block was my 68 Vista Cruiser. Actually, I suspect that was actually a TH375, but I didn't know enough to tell the difference in 1974.

(And don't confuse the TH400-based TH375 with the TH350-based TH375B - clear as mud, right?)

GAOldsman

Crystal

svnt442

Joe I had found the build sheet when we stripped the car.....M40 in the trans box. I remember that very clearly.