85VetteTerreHaute

I was wondering if there was something wrong with my transmission, but then again maybe I just dont understand it since this is the first one I have ever driven.

If I set the cruise at say 55 and flip the over drive button, there is no differance is whine, rpms or anything... Seems to do something though as I can watch my fuel mileage get better with overdrive engaged.

Ive done a little reading on google, but everyone seems to have a differant opinion. Thought someone here might be able to tell me if I am doing something wrong, somethng isnt working right, or what the case might be. Thanks

vetteoz

How do you know O/d is engaged?
What revs at what speed are you doing?

O/d works automatically every time you start the car unless you manually turn it off so the O/d may
already be engaged without you knowing it and the over ride switch is not working to disengage it
which is why you see no change in RPM

1985 Corvette

Open the hood and take a look at your relay. It's not uncommon to see frayed, bare wires where the plug goes into the O.D. relay. Such a state usually effects O.D. operation. It's a start.

powerpigz-51

Does the "overdrive" light come on?

coupeguy2001

if your RPMs are around 1800 at 75 mph, it's working. at 55 mph, you should see around 1200 RPM.
If your RPMs are near 3000 RPMs at 70, it is not engaged.