2000 front differential leak

Noticed that my front differential was wet on the outside but not enough to drip. Just wondering if it is more likely the gasket failing or the seals on the axle shafts? Truck has about 165,000 miles. Is it hard to drop out diff and split the case?

 

Define hard?
I don't see it being hard to do. Disconnect lower ball joints on both sides, pop axles out of diff, 3 mounting bolts on the crossmember and a connector on the actuator.

It could be leaking where the cv's pop in. Then theres the pinion seal or the seal in between the 2 halves of the clamshell. The stub shaft seals against the housing and the actuator seals to the stub shaft.

 

That doesnt seem too hard since I did most of that cv joint work recently....thanks!