Chevy & GMC Vans

I think the 96 vans have a 3.71 rear end. Has anyone ever put something around a 3.2 in it? What would be the effect on performance? gas mileage?

Performance would go down, going to a higher gear, your gas milage would go up for hyw milage, but prob down for city. I honestly dont know if they go up to a 3. something gear set. Highest set i know of is 3.42 but there is alot I dont know about. If your lookin for better hwy mpg go with a 3.53 but i warn ya i had a van with these in it and they have NO low end torq at all. Stop light take off was joke, you measured your 0-60 time in mins.

You can look at the RPO codes on your van to see what rearend ratio your van has.I think I remember reading that 3.70's gearing was a special order and it was highly unlikely to find in many of these vans.The more common gearing was 3.42's.Those codes "I think" are on the passenger door posts for your yr van.Maybe someone will chime in to clear that location up for you.Also,if it is a AWD,you have to change both front and rear gear sets.That have to be alike.

I suggest you find the RPO codes and let us know what they are.

My experience in the midwest is that the 2WD vans have 3.23 and the AWD vans have 3.42. Looking at the RPO codes on the passenger door will let you know what you have. Look for the codes beginning with G. GU5 = 3.23, GU6 = 3.42, G80 = Posi. Any others I'd have to look up.

Another thing you might want to do is head to the parts counter at your local dealer with the VIN and ask for a print out of the RPOs with definitions. It's a handy reference to have.