Rear end question

with both wheels off the ground, If when you rotate one wheel forward and the other rotates backward = Open diff. If they both rotate forward then Sure-grip or limited slip. If sure grip / limited slip - with both wheels off the ground and trans in neutral rotate one tire 360 deg and count the number of times the drive shaft rotates. If the shaft rotates ~2 3/4 times then 2.76, if ~ 3 then 2.93 if ~3 1/4 then 3.23 etc.

If open diff leave one wheel on the ground and do the same as above.