Sure-grip Identification

[boxfox]

If the differential is a sure-grip will it always have a "S" on the side or was that just a 1965 thing?
My particular application I am wondering about is a 8 3/4-3.23-2881489, from a potential seller

[Chryco Psycho]

you can see the springs or clutches inside a sure grip case

[boxfox]

So will there be an "S" on the side to identify it?

[Chryco Psycho]

I have never seen an S stampd on a sure grip & have no clue what you are reffering to

[tactransman]

You have to remove the "pumpkin" from the rearend housing before you can verify what you have.

[boxfox]

Alright maybe I read what I was reading wrong about them..

[burdar]

The different ratios and sure grip combinations were identified using paint marks on the bottom of the center section.  There were no stampings on it that would tell you what was inside.

[Aussie Challenger]

If the axles are still in the rear turn the pinion flange around and both axles should turn in the same direction if it is a sure-grip, or have somebody try to hold one axle still, it won't if a sure-grip. If it is an open then the axles will turn in opposite directions.