I just purchased a 05 2500 and was looking for the gear ratio. There was nothing in the glove box or on the window sticker. I checked the axle tube and for a tag on the diff housing. The only thing I could find was that it was 11.5 rear end. But, I think that's just more fluid capacity.
and has nothing to do with ratio. I was looking at getting 315 tires and I want to know the ratio. Will I get worse fuel MPG? Can anyone help me?

 

Next time you are into the dealer, just ask and they can print out a build sheet (don't know what it is called) which will list all items assembled into your truck. But it should also be on a tag in the glove box of your truck within a list of many items unless someone removed it prior to you getting the truck. I called DC and they faxed me the sheets of which many items mean nothing toi me but still I got all the info about the truck.

Hope this helps...Don

 

Thanks for the reply. I see you have the Quad XZT. How do you rate it? MPG? Power?

 

I have an 05 3500 and there is no info tag on mine either. My 95 had an information tag under the hood with engine, gearing and paint codes. Nothing anywhere on the 2005.

 

If you can't make it to the dealer another way is to block the front tires jack and jack the rear end up just so the tires clear the ground. Put it in neutral and mark the driveshaft and tire then spin the tire 1 complete revolution and count how many times the driveshaft rotates this will give you a pretty close estimate on which gear ratio you have BTW its should be either 3.73 or 4.10 depending on which options you have ie. towing package. If you have the powerwagon you should have 4.56 gear ratio. hope this helps...

 

What are your rpm's at certain speeds and which tranny do you have? You still have the stock tires (265/70/17's) I take it.

For instance, my stock tire equipt NV5600 6 speed Cummins turns ~ 2100 rpms, in 6th at 70 mph and I have the 3.73's.

 

Auto or manual? if it is a manual, is reverse right and up or left and down? Rev up right and up is a NV5600 and can have 3.73 or 4.10's. Rev. left and down is the G56 and it only comes with 3.73's. the auto can have either gear ratio.