Need help very confused
- Thread starter TimothyOnTop
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Thank you I didn't even see that message somehow thank you for taking the time to explain things I really appreciate it. There is no plug on mine I just looked and I also looked earlier and the rear end was upgraded to a 12 bolt gm at sometime and I thought it was all stock. I figured out the hard-line on back of carb runs to brake booster and the other one runs from. Manifold vac port to transmission is a hard line all the way except a 4 inch rubber piece that connects to transmission. All the lines are anchored inside the frame so someone took the time and did a really good job it looks way better than stock. I'm glad I rebuilt the carburetor because I would still think I had th200c with a 7.5 inch rear end
Hopefully next time I open the hood it will have a beautiful 402 in the engine bay 🤣
402 what? Big block? Then you may be moving up to a TH400 maybe. Depends on what's inside that TH350. Obviously they didn't do a very good job of finishing off hooking up the kickdown cable to the carb. Good thing about the TH400 is the kickdown is electrically controlled so it doesn't matter if you use a carb or not.
Just some reading for the TH250/TH350.....
procarmanuals.com
This link is basics about the various GM Transmissions...
www.crankshaftcoalition.com
PDF ONLINE - THM 350/350C – ATSG (Automatic Transmission Service Group)
THM 350/350C – ATSG (Automatic Transmission Service Group). This Manual covers the procedures necessary to diagnose, repair and/or overhaul the 350C transmission and the 350 transmission. GENERA L DESCRIP TION, DIAGNOSIS, TEARDOWN, PUMP, VALVEBODY, ASSEMBLY, SPECIFICATIONS, 350 SUPPLEMENT...
procarmanuals.com
This link is basics about the various GM Transmissions...
General Motors transmissions
www.crankshaftcoalition.com
69HurstOlds, re TH400, electrically controlled kickdown? What initiates the demand downshift, a solenoid on the throttle lever, or a VOES switch that uses vacuum to determine when to close the circuit and signal for the shift to occur? Me here being personally curious because I happen to have a Corporate BOP TH400 sitting on the transmission trolley and externally i saw no sign of a socket for electrical input. The box came from a early 70's full sized Pontiac Wagon that had a 400 mill for an engine. Neighbour was a fanatic about Pontiacs and raced them at the local dirt track. Know I mentioned this some time back but the T-mission came into my hands because a scrapper was cleaning out Jack's lean to when the house was sold and I paid him off so I could rescue it. May never find a use for it but at least it didn't get converted into a set of teflon non-stick frying pans!
Nick
Nick
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The T400 lockdown switch is a normally open slide switch that resides above the gas pedal similar to the G-body A/C shutoff switch cars that had the switch configuration. Excepting the G-body switch is normally closed. It’s that way on late 60s and 70s T400s used on Oldsmobiles. Single connector on driver side of transmission case.
I'll look at the one I have, just out of curiosity. It's a BOP th400 long shaft from large sedan/wagon. Not sure of year. The kick down is electric, at least every one I ever dealt with. The 1 to 2 upshift as its safety feature is in the valve body and have to change that out to keep its shift from occurring.
For the TH400- below in the red circle is where you should find the single pin connector for passing gear (they call it a detent solenoid). Some have a double pin connector, as the other one would belong to the Transmission Controlled Spark (TCS) system. It was an ancient emission system starting in 1971 I believe, which controlled waiting until advancing the spark until high gear or some sh*t like that.
Here's how it hooks up wiring-wise.
Detent solenoid shown in red circle below.
Here's how it hooks up wiring-wise.
Detent solenoid shown in red circle below.
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