1. Locate the rear differential. The rear differential is located under the vehicle, between the rear wheels. It is typically a round or oval-shaped housing.
2. Determine the number of bolts that hold the differential cover in place. The number of bolts will vary depending on the model of your Chevy pickup. Count the number of bolts to determine whether there is a 6-bolt cover, an 8-bolt cover, or a different number of bolts.
3. Remove the differential cover. Once you know the number of bolts holding the differential cover in place, you can remove them using a wrench. Be prepared to catch a small quantity of gear oil that may leak out when the cover is removed.
4. Look inside the differential housing and locate the ring gear. The ring gear is the large gear inside the differential. It is typically attached to the differential carrier.
5. Count the number of teeth on the ring gear and the pinion gear. The pinion gear is the smaller gear that meshes with the ring gear. The ratio between the number of teeth on the ring gear and the pinion gear will tell you the gear ratio of the rear differential.
For example, if the ring gear has 38 teeth and the pinion gear has 11 teeth, the gear ratio is 3.45. This means that for every three and 45/100ths of a revolution the pinion gear makes, the ring gear will make one revolution.
6. Replace the differential cover and tighten the bolts to the specified torque. This information can be found in a repair manual for your specific model of Chevy pickup.
