66 1/2 ton gmc axle seal replacement

[66gmckid123]

As a novice to the car world I need some help. I have leaking axle seals, confirmed after I redid the brakes. I have the dana rear end, and would like some tips on how to remove the axles to replace the seals. It's leaking right at the backing plate and I couldn't find a diagram or locate a manual for this year truck to help me out. My uncle told me it's not hard, coming from a mechanic, but he couldn't remember if the axles are pull out or not. Any tips would be much appreciated.