frt diff output seals

The right side seal is leaking on a 2004 GMC Sierra.Is it easier to remove the diff assembly to do the job or can the seal be replaced on the truck?Would it be advised to change both sides if the diff is going to be removed?Any special tooling required?I have read to disconnect right axle tube from the diff housing and proceed to disassemble the components to reach the leaky seal.Is it just that simple?The left just requires the axle shaft to be popped out and the seal is then acessable once the shaft is out of the way?I have not done this before and want to get as much info before procceeding to do the job.Thanks

Chuck's

The axle stubs will not come out without any really heavy blows with a good BFH.Slide Hammer will not work,tried that too one one with one with bad diff bearings.GM put the worst wire clips in and the stubs are a PITA to get out.

Accomplished the task.I was able to remove the right side axle tube assembly from the diff housing.Just a little bit of wiggling the tube out of the vehicle.The only problem I had was trying to keep the tabed thrust washer from falling out of the grooves.I jammed two wedge shaped pieces of wood between the axle flange and the axle tube.This put pressure on the thrust washer and kept it from falling out of the grooves.Worked great and the tube just lined right up.I hope this will help others who may attempt this task themselves.
chuck's