I have the pinion seals on both front and rear axles leaking on my '99. Its the Dana 30 front and Chrysler 8.25 rear, how hard is it to replace them?

 

It's as simple as taking off the axle cover, draining the gear oil. Putting new seal on, put the cover back on then fill it with gear oil from the fill hole. You can even paint the diff. cover while its off if you want to.

 

Ummmm... those are diff cover gaskets, I am talking about pinion seals, those seals in the back of the diff that have the yoke going into them.

 

Mr. Grimm, Hayden is talking about the fact that you have to drain the differential fluid to change the pinion seal, otherwise the fluid will come out when you take out the pinion seal.

here is a nice video about it.