Follow up Re: <VV> PG no reverse and more

John Kepler jekepler at
Mon Dec 10 09:30:08 EST 2007

I'm not sure of what you're talking about. 
The 'manual' valve isn't the same 
as the 'throttle valve'.

No kidding!  But then the "throttle valve" is the only one that anyone
around here seems to want to talk about!  

 And I've never heard of a PG shift cable 
stretching. Not saying it can't, but I've not heard of this.

Want me to send you a couple?  I've fixed at least 3 PG's whose problems
were directly related to stretched/worn/partially broken shift cables (FWIW,
a worn interior sheath creates a "de-facto" stretched cable, even if a
tape-measure shows the proper cable-length)!  If you've got a PG with goofy
problems (like "dropping a shift" between low and high, "roughness" and/or
drag in neutral, and delayed shifts into reverse), the Manual Valve
adjustment is the first place to look.  If the Manual Valve adjustment using
the GM PG Gauge Tool (sorry, I don't have the number off the top of my head
because I made my own) is limited out, then it's because the cable has
broken/worn/stretched, and must be replaced!  

Best (and easiest) way to check the 'manual' valve alignment is to SLOWLY 
move the dash mtd. shift lever between segments (detents), and listen ( 
feel) the tranny shifting. If the transmission shifts (changes mode) at the 
hump in the dash lever's travel, that means the cable and 'manual' valve are


Not necessarily.  It CAN give you a "heads-up" for a really BAD condition,
but isn't precise enough to be enough of a "tell" if the valve is only
slightly out-of-alignment.

Oh, Mr. Yarnell, every Corvair PG was built at the GM-Hydramatic Plant in
Toledo, Ohio.....guess where my Dad worked!  


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