You think you're an expert? EXPLAIN THIS!!

Since early this year, my 440-T4 transmission has had a very delayed and harsh upshift when going from 1st to 2nd gear.

I literally researched for hours and hours, days, weeks, months. I had a complete tranny service with New Vacuum Modulator. It seemed like NOTHING worked. I basically just came to the conclusion that my tranny was almost dead, and would one day soon have to be re-built.

Now, here in November, as the weather is getting colder and colder, I notice that my cars engine is taking TOO long to heat up. I notice that when I turn the interior Heater ON, the temp drops even more, sometimes down to around 130 degrees(verified with Scanner).

Seeing as this was an obvious symptom of a defective thermostat that was stuck pretty much completely open, I decide to replace it today with a New AC Delco t-stat.

Here's what I need someone to explain:

My assumed-to-be-dead transmission is now shifting PERFECTLY! I even seem to have better throttle response and acceleration, but the main thing is the 1-2 bang upshift is completely GONE!!!!!!!!!!! What the hell!!!!!!!!???

How can a NON-ELECTRONIC(besides torque converter) transmission from

1989 be cured by simply replacing a thermostat!!??

The car in question is a 2.8L MPFI Cutlass Supreme with a 195 degree t-stat.

ANYONE??? I am totally baffled by this! I know that the t-stat wasn't allowing the car to reach "operating temperature" but WHY in the heck would this make a Vacuum Modulator and TV Cable controlled transmission have a harsh 1-2 upshift??

THANKS!:)

Reply to
OldsFan4Ever
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Does it run the tranny fluid to the radiator to regulate it's temperature? If so, I would guess that one or more parts of the transmission weren't getting up to operating temperature and this caused the problem. Once it started getting warm again whatever was affected started to function properly again.

Reply to
Brent P

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