Hello,
I am new and own a 2012 Ram truck. I simply have a question.... I am in the process of looking into buying a 2500 Diesel... I am looking at used newer trucks (2015-2017) at this time and want to make sure that I am looking at the truck I want with the correct rear end gear to get the best fuel mileage when not towing. I know the information is the VIN number. So I have looked at several VIN numbers but its confusing because there are ratios for every gear from 1 through 6. But then theres an Axle ratio.... and there are several gear ratios from 4.10 to 3.23... How or which one is the correct gear ratio? Help please. Thanks!

 

You are interested in the rear axle ratio. Biggest question is, how much, and how often, do you actually use your truck AS a truck? What is the weight of the trailer you tow? Most are going to have an automatic trans, and they will all have pretty much the same gear ratios. Rear end ratio is what plays the biggest role in just how much your truck will tow. Of course, if you are more concerned about fuel mileage (on a one-ton truck???? Really????) the the lower (numerically) the gear ratio, the better your fuel economy will be, and the lower your maximum tow rating will be.

 

if you are more concerned about fuel mileage (on a one-ton truck???? Really????) the the lower (numerically) the gear ratio, the better your fuel economy will be, and the lower your maximum tow rating will be.[/QUOTE]


I don't know if you are a professional trailer hauler but for the most part, I do drive to work and back and would like to get the best savings on fuel when possible.... I plan on pulling a travel trailer but not on a regular basis.... So as to answer your "Using it AS a truck" comment, I don't know if you are doing the same.... As for me, maybe a weekend a month pulling a travel trailer. More often a boat trailer that I can pull with my 1/2 ton.... and I know that the lower the number on the axle gear is what will give you the better mileage.... that being said, and again repeating my question.... The VIN number has the "AXLE RATIO" with all three gear numbers on it... WHICH ONE IS THE CORRECT NUMBER TO DETERMINE THE ACTUAL GEAR RATIO?

 

You are probably going to have to crawl under your truck, and see if there is a tag attached to one of the cover bolts on the rear diff. That *should* tell you the gear ratio in there. Normally, I would expect the build sheet to specify which one you actually have.....