We offer a full line of equipment and truck differentials and parts by Spicer, Eaton, Rockwell, Meritor, Mack, Dana, Fabco, Marmon Herrington, International, Oshkosh, FWD, Timken, Clark. Global Differential Supply. Your one-stop differential, ring-pinion, crown wheel-pinion supplier for Kenworth, Peterbilt, Freightliner, International, Mack, Ford, GMC, Crane carrier, CCC. Autocar, Western Star, and Oshkosh trucks.

How do I know what my gear ratio is?

Your axle gear ratio determines how many times your driveshaft rotates for every full tire rotation. The gear ratio can often be determined from the vehicle’s VIN code or listed on the axle tag. Some manufacturers, may not include that information in the VIN. The ratio can also be found by dividing the number of teeth on the ring gear by the number of teeth on the pinion gear.

[ Ring Gear Teeth / Pinion Gear Teeth ] = [ 41 / 11 ] = [ 3.73 ]

Calculate your gear ratio below by entering the number of teeth on your ring gear & pinion gear.

ring & pinion gears

Gear Changing Tips

Larger tires aren’t the only reason you may need to change gears:

Many truck owners swap gears for better mileage.
If your vehicle is a 4×4, you will need to change the gears in both front and rear axles.
Most front axles require reverse cut gears because front driveshafts typically spin the other way.
Front and rear gears can be different by 1% on road and 2% off-road without impacting performance.

If you have any questions or need assistance, give us a call.

Ask An Expert >>
Click to Visit Our Differential Manuals Page

Select your make below:

Rockwell Differential
Mack Differential
Volvo Differential
Spicer Differentials
Fabco Differential
Marmon Herrington Differential
Meritor Differential
Oshkosh Differential
International Differential
FWD Differentials
Eaton Fuller Differentials
Timken Differential

Differentials, Ring and Pinion, Crown Wheel and Pinion, new, used, rebuilt and exchange. One call does it all. We have all models in stock ready to ship worldwide today. One call to us and we can provide international shipping.

Our experienced staff can help you find the Differentials you are looking for. If you don’t see the Differentials you need on our website, please call us at 877-776-4600, we will be glad to assist you