What are these rubber pieces on my 2007 tahoe rear diff fill plug?

[Geotrash]

I guess when I pull the cover I'll know if there's a gasket or rtv was used. I'm hoping gasket so I can re-use it. Otherwise I'll have to clean it up really good and use RTV to put it back on, which I've never done. And, it'll be in a cold garage - which I read you should only use RTV in temps 65 degrees or higher. That might be April before I can use it..lol..it's going to be only 25 degrees for a high for awhile here in Nebraska...

Ah, Midwest winters! I don’t miss that when there’s work to do on the car.

Why not order a gasket from Rockauto to have on hand for the job just in case the one that’s there is trashed? My guess is that whoever pulled the diff just added RTV to the gasket to prevent a comeback (totally unnecessary). I’m 100% sure that the rear diff cover uses a gasket on your rig and not just RTV.

 

[dpx2]

I could do that too! I think I'll follow that suggestion, thx!

 

[Rocket Man]

I guess when I pull the cover I'll know if there's a gasket or rtv was used. I'm hoping gasket so I can re-use it. Otherwise I'll have to clean it up really good and use RTV to put it back on, which I've never done. And, it'll be in a cold garage - which I read you should only use RTV in temps 65 degrees or higher. That might be April before I can use it..lol..it's going to be only 25 degrees for a high for awhile here in Nebraska...

I wouldn’t use RTV to seal the rear cover with, you’ll get the same result with RTV inside the cavity. LubeLocker makes an awesome gasket for the G80 that is reusable. Guaranteed to never leak and it’s easy to install.
Part # is LLR-G850.