Birge,
There are a couple other ways to tell the ratio, (which is the ratio of ring gear teeth to pinion gear teeth).
1) You can count the number of teeth on each gear (i.e. 41 Ring gear teeth & 10 Pinion gear teeth =41/10 or 4.10 ratio) or
2) The number of teeth should be stamped on the end of the pinion gear shaft, which is visible from the inside of the differential-you may need to reach in and clean off the end. You'll see a bunch of numbers but some will read something like "GM-7-32" which would mean 32 ring gear teeth/7 pinion gear teeth =4.57 ratio. This method is easier.
