73 charger rear end missing tag

[texas charger 73]

Not sure what rear end I have as the tag is missing. Any other way to find out without cracking open case? Also gear ratio?

[ODZKing]

From one of the other forums:
Jack the vehicle up, put jack stands under the rearend. Turn one tire, if the other tire turns the same direction it has an sure grip rear end.
Then for gear ratio, count the number of turns the driveshaft does for one turn of the rear tire.
It will give you a rough idea.  To know for sure what the car came with, you'd need the build sheet.
But I am sure there are other ways to tell with dis-assembly.

[texas charger 73]

I have fender tag. That's about only marking

[ODZKing]

Yeah, not on there like the earlier cars. 

[John_Kunkel]

From one of the other forums:
Jack the vehicle up, put jack stands under the rearend. Turn one tire, if the other tire turns the same direction it has an sure grip rear end.
Then for gear ratio, count the number of turns the driveshaft does for one turn of the rear tire.
It will give you a rough idea.  To know for sure what the car came with, you'd need the build sheet.
But I am sure there are other ways to tell with dis-assembly.

If it doesn't have Sure-Grip, jack only one side clear of the ground and turn the tire two full turns while counting the driveshaft turns.