gear ratio

Type in your VIN number here in the box next to Equipment Listing, hit search, you'll get every detail of your truck as built from the factory. you can print it or save it as a .pdf file for later.
Ram Truck Equipment Listing

Should be a sticker in the glove box. or a tag on the rear axle.

If you let us know your tire size and a speed @ engine rpm in a specified gear, preferably 4th gear, we could tell you.

If you go to this website:

https://www.dodge.com/webselfservice/dodge/index.html

and click on "equipment list" (link on lower left side of page), enter your VIN number you should be able to get a list of the equipment in your truck including the gear ratio.

Glove box. If it has 4.10 it will say so. Otherwise it has 3.73.

If buying used...the previous owner(s) might have changed the diff gear set. This is from an old thread on HOW2 without lifting the vehicle


2500 Suburban - How to determine ratio?

Best to then tie/tape a length of string on the drive shaft. Note a
datum.

Then roll the vehicle one tire rev using the valve stem as a datum

Count the full turns and the fraction left. That is the diff ratio
and makes no matter what size tire or suspension lift, etc.

Remove the string.