How do I find the axle ratio on my GMC Sierra?

Identify your GMC or Chevrolet rear end gear ratio by the RPO Codes, usually located on the placard labeled “Service Parts Identification” inside the drivers door panel or glove box.

How do I tell what gear ratio my rear end GM has?

Count the teeth on the small gear in the forward part of the axle housing, called the pinion gear. Count the number of the teeth in the big ring gear attached to the differential. Divide the number of teeth on the pinion into the number of teeth on the ring gear. This is the gear ratio.

What is the best rear axle ratio?

The most popular rear end ratio in trucks today is the 3:55, which sort of averages towing power and fuel economy. This is a good ratio for the occasional towing or hauling individual. For a person who tows more often, and heavier loads, the 3:73 or 4:10 may be more appropriate.

How do I identify my 8.5 GM rear end?

When looking at the housing from the rear, an 8.5 will have two squared off chunks of casting hanging on each side near the bottom of the differential. An 8.2 (shown) will have the same contour as the cover. Most 8.2 factory covers also have the strange protrusion at the top.

What does the 8th digit in a VIN number mean?

8th Digit: The 8th digit, in this case, a “Z,” is one of my personal favorites. It’s the engine size! So if you were to go to a junkyard, this digit is really helpful for vehicles that had two different engines during the same year. An S10 Truck or an S10 Blazer are perfect examples of this.

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.

Where can I find the axle gear ratio?

GM RPO Axle Codes. To find the axle gear ratio of any GM vehicle, locate the RPO sticker (typically located in the glove box) and write down any codes starting with F, G, or H. Then, find those codes in the table below.

What’s the axle ratio on a GM transaxle?

GM RPO Codes – Factory Identification Labels and Interpretation RPO Code Description Ratio G11 Transaxle Final Drive 2.56 G44 Axle Rear 3.07 G72 Axle Rear 2.14 G75 Axle Rear 3.62

Where do I find the gear ratio sticker?

You need the RPO code of the sticker in the glove box. The code for the gear ratio will match one of these. What he said. He covered it all. You need the RPO code of the sticker in the glove box. The code for the gear ratio will match one of these. So just match one of these numbers with the many numbers on the sticker and you’re good to go?