[jeepinwi]

You can either look on your window sticker or you can crawl under the truck. There should be a sticker on the rear axle saying the gear ratio...3.21, 3.55, or 3.92.

Also, you could tell us your tire size and RPM's at 70 MPH. We could calculate which ratio you have that way.

 

[TransEngineer]

If you'll post the last 8 digits of your VIN, I can look up the gear ratio for you on Tuesday when I'm back at work....

 

[bigslammy]

Window sticker just says anti spin diff has no tag on the cover bolts so I see tomorrow what the rpm is with speed thanks

 

[Dragvan]

The 3.55 is standerd so if it only has antispin diff. I would assume the 3.55s are in it.

 

[DWWHemiguy]

If you have a 3.55 and want to upgrade to 3.92 would the dealership swap it out ? Would it be to expensive to do it that way?

 

[NTD13]

Swap out?

Swapping out would be pretty expensive. A few thousand I believe. The 3.92 helps with acceleration and towing.

 

[Dragvan]

If you have a 3.55 and want to upgrade to 3.92 would the dealership swap it out ? Would it be to expensive to do it that way?

It wouldnt be worth it. They would charge you way to much at the dealer. Also if your going to change the gear from a 3.55 go for a 4.10 or 4.56. I would just stay with the 3.55 You have the posi and thats more important then the .37 differance in gear.