It sounds like you need to add transmissino fluid. It could also be a vacuum line that has come loose from the transmission.
Dynaflow was the automatic transmission used in Buicks from the early 1940's until l966
Because you don't have enough the transmission fluid in the system.
mine was acting up too. took me forever to find it. it was the range sensor.
Throttle position sensor
If the transmission would not shift, YOU would not go at 60 Miles Per Hour.....
If your transmission doesnt shift until 35 mph then check your vaccum hose on your transmission.... i had the same prob. and that is what it was because it is a vaccum shift tranny and without the vaccum then it will shift at really high rpms.
i have a 200 f150 p/u if I put my foot into it it will accellerate and shift as it should until 60 mph. at that time it will over rev and I have to slow down and dissengage over drive.
The transmission throttle valve cable needs to be adjusted.
NO, The book says every 50,000 miles but i have never seen one fail until 125,000 miles.
have the tappet settings checked.if automatic lfters,check engine oil for correct level correction, not automatic lifters,hydraulic lifters
In 1992, it was called the Sunbird. The Sunfire did not come out until 1995
Yes , it won't shift into overdrive until the speed is fast enough anyway , it's the 4th speed of the automatic transmission