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!:)