Rear Axle Seal

[PartyPooper]

Hello, I've searched the site but I'm still looking for a little advice because I'm a bit confused.

I'm a proud but sometimes frustrated owner of a 70 GMC Grand Sierra 3/4 Ton truck.

It looks like I need to replace my rear axle seal. Apparently I'm looking for a lock screw so I can remove the pinion shaft from my differential. I can't seem to locate that screw. Also, because it appears my rear axle is different from those I've seen I thought there might be a different procedure for removal.

Any help is appreciated, the gear is labeled Dana 32503 A808 46-13 (if someone could also help me identify the rear end type). Thanks - Earl