Hello & advice needed, leak on front drive shaft output

[Steve N 69 69 69]

Hello, I haven't posted for a while. My name's Steve, I bought Nate's ( 71Blazer ) K5, and drove it down to L.A. Ca. from damn near the top of Wa. ,1200 Mi. in 2 days.
I've been doing some little upgrades, as problems arise. I installed a new CS144 140 amp alternator ( the stocker crapped out on me 10 mi. from home on my way down). a new jegs heavy duty Alum. water pump ( stocker started leaking in the middle of the desert, while I was at a MDR race) and some other little things I'll post pics of, like a new pass. fender ( fun to line up...not) and Auto meters in the factory cluster.

what I need advice on is a leak that drips (runs) off the front drive shaft, I'm assuming its from the transfer case, which is a NP205. Is there a seal thats easy to replace there? where should I get one? Dealer?
Thanks, Steve N