i have a 96 ram 2500 auto and was wondering how the overdrive is supposed to work. it is a push button on the dash but cant figure it out.

 

The button disables the overdrive operation when you push it in and the light comes on.

Normally the trans shifts intooverdrive on it own at around 60km/hr

go for a drive on the highway once you get up to cruising speed push the button on and off. you should feel the trans shift back and forth between 3rd and 4th gear (overdrive) and you engine RPMs will go up and down a few 100