Sure, if it's locked, jack up the rear end and spin the drive shaft till the tires turn ONE revolution, counting the driveshaft turns.. number of DS turns is the gearing..
5 and a LITTLE is 5.13  four and a little over half is 4.62.... etc....
if the rear end ISN'T locked, jack up ONE rear wheel and turn the Drive shaft until the tire in the air makes TWO revolutions (to make up for the diff) and count the turns.. same thing as above
You are looking for 5 and TOUCH less than a half turns of the driveshaft