Author Topic: TH350 shifting too high  (Read 154 times)

Offline septantrionalis

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TH350 shifting too high
« on: January 08, 2019, 09:36:17 PM »
So I drove my truck home and it shifted fine from 1st to 2nd gear at around 1800 RPM.  I needed to clean up the engine and removed the passenger side valve cover.  I put it back on and started to drive around... only this time, the truck is shifting at around 3000 RPM now.  I'm no mechanic, so I'm not sure what the problem could be, but I probably accidentally disconnected something.  Can someone suggest what I can look at?

Someone suggested the vacuum hose.  I'm not 100% sure what to look at.  From my understanding, that hose is connected to a modulator valve on the side of the transmission.  Where does this hose connect to on the engine or is it connected to the carburetor?

I also saw a hose go from the carburetor to a silver looking thing on the side of the distributor.  Not sure what this is, but it looks intact.

Could the kick down cable cause this problem too?

My truck is a 1974 Chevy K10 with a 383 engine, Holley Avenger Carburetor, TH350 transmission, and NP203 T-Case.
« Last Edit: January 08, 2019, 09:51:02 PM by septantrionalis »

Offline septantrionalis

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  • Posts: 49
Re: TH350 shifting too high
« Reply #1 on: January 08, 2019, 10:58:09 PM »
Nevermind, I got it.  The hose fell off of the modulator valve from the transmission.  No idea how that happened.  I plugged it back in and its shifting fine now.