i have a dana 30, 27 spline and my differential fluid is leaking out of the axle tubing onto the passanger side spendal. how do i go about fixing this?

 

Do you have the vacuum disconnect axle?

 

Gotta pull the carrier which involves pulling the axles which involves pulling the hub assemblies. Also you need to create a sort of tool to seat the seals.

Edit: I forgot, it does depend whether or not you have the vacuum disconnect, like he asked above.

 

no vacuum, just straight axle

 

Ah, well then everything I said above :P
Heres a good writeup http://go.jeep-xj.info/HowtoD30AxlesSeals.htm