How can I find out the size of my rear differential?

This identifies the differential — a Ford 9-inch or GM 7.5-inch — for example. A diagram of the ring gear is found in Resources. Rear differentials can be visually identified by finding specific characteristics of each differential. This will identify the differential size when compared to the charts found in the Resources.

How to find the gear ratio of your rearend?

If you have the rearend opened up where you can see the gears, count the teeth on the ring and pinion. Divide the ring teeth number by the pinion teeth number. Example: 41 teeth on the ring and 10 teeth on the pinion = 4.10 gear ratio… Return from Gear Ratio to Drivetrain

How do you identify a GM 12 bolt rearend?

A numerically larger ring gear will physically bolt to the differential, but you will not be able to get the pinion-and-ring gear to properly mesh. The carrier “Type” can be identified by measuring the distance from the carrier bearing shoulder to the flange where the ring gear mounts.

When do you know if your rear end is open?

If the other tire turns the same way or doesn’t turn at all, you should have a posi or limited slip. If the tire turns opposite of the way the first tire spins, then it’s probably an open rear end. If you have a car with a posi or limited slip rear, jack up the car and get both rear tires off the ground. Now put your jackstands under the axle.

Where do I find my rear end ratio?

The table below will help you determine what rear end ratio you have by using your RPO code, answering the question: What rear end ratio was in my Chevrolet or GMC vehicle when it left the factory. You can typically find your RPO code on driver side door panel or glove box.

How is the size of the rear differential determined?

The size of a rear differential, or rear end, is determined by the diameter of the ring gear inside the differential housing.

How can I find out my rear axle gear ratio?

Another way to determine your rear axle gear ratio is to open the door and look for the Vehicle Certification (VC) tag.

What’s the rear end gear ratio in a GMC?

General Motors rear end differentials are referred to by the diameter of the ring gear, i.e. 7.5 inch, 8.5 inch, 10.5 inch. Our experts will help you find the correct ring and pinion set for your particular application.