What is part number 3? Front differential seal replacement..

Hello everyone.

I have some sweating from my front differential driver side seal. This seems to be a common problem, and fairly easy to fix.

However, when looking for the correct seal from GM oem parts web site, I am confused by the part numbered 3 on the illustration. This part is not listed. Part number 4 is axle output seal.

To those who have done this repair: What is the part numbered 3? Also, why is there a listing for a non-crew cab Ava for the seal?

https://www.newgmparts.com/auto-parts/2003/chevrolet/avalanche-2500/base-trim/8-1l-v8-gas-engine/front-drive-axle-cat/axle-shafts-and-joints-scat

Thanks!

Part 4 or 3

12479155

This site shows it a little better and you can zoom in on it. Shows the seal and ring, probably a snap ring.


http://parts.royaloakschevy.com/a/Chevrolet_2003_Avalanche4WD2500-LT/_51506_5860420/K143-DIFFERENTIAL-CARRIERFRONT-AXLE-PART-2-925-RING-GEAR-K143-DIFFERENTIAL-CARRIERFRONT-AXLE-PART-2-/050420TC06-695TC06-695.html