<VV> question for the Powerglide experts...

[Zoltan Szilagyi]

Hi folks,

The Powerglide on my '66 Monza (with stock 110 engine) has been acting up
lately. Full-throttle downshifts should never happen above 45 mph, but in
the last 50 miles or so of driving, they have started happening at speeds as
high as 60 mph, which results in pretty high RPM in first gear. Everything
else works perfectly, including upshifts under all sorts of conditions. I've
driven the car for many years and this problem only began very recently; I
haven't changed the throttle valve adjustment or anything else. The ATF
looks and smells good and the fluid level is correct.

Does anyone have any suggestions for narrowing down the problem? It seems to
me that at those speeds, it's the governor's job to prevent downshifts
irrespective of throttle position. However, I had a failed governor about
three years ago and the symptoms were different: no upshift at all,
irrespective of throttle position; replacing the governor with another used
one cured that. Therefore, I wonder if there is something internal to the
valve body that could go wrong and trigger this particular behavior. Rather
than "diagnosing by replacement," it would be great to know what to check in
the current valve body (or elsewhere).

Thanks,
Zoltan Szilagyi
Corvairs Northwest -- Seattle, WA