how do i find out what rear end i have in my 97 12 valve dually?

 

There is a tag under the the hood, that states what the truck is equipped with such as the type of axles and gears. But a dually comes with a Dana 80.

 

i meant the gears

 

call dealer and give parts guy vin off truck they can tell you. if it has been changed you have to do the old fasioned way and divide number of pinion teeth be ring gear teeth

 

thanks for the info

 

There will also be a tag on the diff cover, maybe covered with grim now like most, but the tag on the axle says what came factory with the truck.

 

what are your rpm's at 70? if they are around 24 2500 u have 4.10s lover than that lik2 0r 2150 u have 3.55s

 

mine said 3.55 on the tag in the hood

 

Don't they also say the gear ratios on the tag inside the driver door?

 

My tag under the hood said 4.10. I had an idea that perhaps that was wrong. I jacked up the back of the truck, put it in neutral, and turned the wheel by hand while counting how many times the driveshaft went around. I got about 3.5.