Curiosity was killing the cat, I had to go back for a look today to see what was under that Escalade. It appears to be a 14 bolt rear axle, is this what the SF(semi-floater?) looks like? If so, then I'll need to keep an eye out for another. Someone removed the cover and I think one of the spider gears from the diff. That's how it seems anyway when spinning the axle shaft from the outer end. Unfortunately the glove box is gone from this Escalade so I have no way to verify by the RPO code. I wanted to see the RPO's to see what gear it has in it to see if it would match my 3.73's.
The reason this rear axle has interested me, and the curiosity got the best of me is my existing 2004 Tahoe Z71 rear axle has 328k on it and will soon have an lq9 6.0 in front of it. It is quiet and running well but how long will it last. It's been serviced twice in it's life. So far so good.