While working under my car I noticed a fairly large surface on the right side of the differential was saturated in dirt/fluid mixture. The left side of the diff and around the pinion seal were saturated too, just not as bad.

Am I going to need to replace all of these seals? or could this mess be from something else?

 

Clean it up, check the fluid, and look for leaks. Additionally, check your CV boots for tears or loose clamps.