How do you tell gear ratio on Chevy rearend?

Answer 1

There is s serial # or model # listed on the rear axle housing. With this # any GM dealer can tell you the ratio. You could also open it up and count the teeth.

With all respects I'll finish the answer. Count the teeth

On ring gear,Then on pinion gear. Now divide the small # into the large #

And that will be the gear ratio

An easier way may be to simply chock the front wheels, jack up the rear end on the differential, place the vehicle in neutral, and while an assistant turns a rear wheel, count the number of times the driveline revolves for one revolution of the wheel. it'll be something on the order of 3.75 (3.73-1 ratio), 4 (4.11-1), or 3.5 (3.53) revolutions of the driveline per one rotation of the wheel.