Jim Grant's Tech Tips
'90 Oldsmobile
Regency 98, No Up-Shift Transmission
Q:
I bought a ‘90 Oldsmobile
Regency 98 really cheap because the transmission wouldn’t shift. So I changed
the transmission with one from a junkyard and still the problem exists. What
makes a transmission shift?
- Joe
A:
Depending on what transmission
your vehicle is equipped with it could be as simple as a throttle valve cable
adjustment, vacuum modulator problem or the governor is binding. It could also
be that the used transmission you installed was just as bad as the one you took
out. Older transmissions such as the one in your vehicle have test ports. These
ports allow for pressure gauges to be installed for diagnosis. The manufacturer
provides allowable pressure specification for each mode of transmission operation.
This allows for diagnosis of worn, sticking or leaking internal components.
If there are external adjustments such as a cable for a throttle valve or a
vacuum line for a modulator, be sure they are connected and working correctly.
After that, you need to have a qualified transmission technician diagnose your
problem. If you don’t want to visit a transmission shop you can practice
changing the transmission until something works.
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