An easy way to check the differential gear ratio without disassembling the car:

1. Lift one rear wheel. Leave the other wheels on the ground.
2. Mark the position of the lifted wheel and the rear propshaft with a marker.
3. While turning the lifted wheel twice, count how many times the propshaft rotates:
   • The propshaft turned five times and a bit: 5.125
   • It almost reached five turns: 4.875
   • It made slightly more than four and a half turns: 4.625
   • It made just under four and a half turns: 4.3
   • Almost four turns of the driveshaft: 3.909