I was wondering where is the vent for the rear diff on a 97 12v dually. My rear end is building pressure and leaking oil, I know there is a vent I just can find it. I also want to know where the vent is for the front diff is also?

 

Not sure on a 97, but generally they are on the top of one of the axle tubes, drivers side usually. It may look like a cap on top of the brake line "T". Or it could have a long hose attached and run up to the top of the frame rail.

 

Yep, there is a small rubber hose coming off the top of the brake line T(drivers-side of axle), which runs straight up past the spare tire.

 

Front end vent terminates right under the air filter box.

 

Thanks