I've been driving the C10 more frequently and the old pinion seal in the 12 Bolt went from a slight leak to just PUKING oil after a drive. Decided to slam a new seal in by pulling the yoke. I had a piece of 2.5" exhaust tube that fit perfectly in the seal, greased it up and tapped it into place around the pinion gear. Put it back together and tried to match the backlash how it was before.
I needed to go for a test drive and make sure its no longer leaking, so took the truck out for a 30 min drive around my neighborhood... I must be old, because it's too loud. This truck is quite raw... I'm not sure how to better describe it; the C10 is a loud, obnoxious yet beautiful beater!
Back in the shop 24 hrs later, not a drop of gear oil on the ground... great success! (pretty sure I filled it back up... ).