Chevy Lumina APV Minivan

We just purchased a 1996 Lumina APV with the 4 speed overdrive transmission with only 54,000 miles on it.. I am coming from a Dodge Caravan. It seems that the transmission may be shifting late. Can you tell me at what speeds it should shift from 1st to 2nd, 2nd to 3rd and 3rd to 4th?

Thanks for your help.

shift points will vary depending on throttle position, load, temperature, final gear ratio etc.... so there is no definite speed at which it should shift. If your van has a tachometer, under light load, and when your not in the gas hard, the tach shouldn't reach 3,000 rpm before it shifts to the next higher gear.