Ring and Pinion Gears

By using the correct gear ratio for your transmission, vehicle, and tire setup, ring and pinion gears can drastically improve your acceleration at the track. The correct ratio can be determined with the help of a ring and pinion calculator. Lightweight gear sets decrease rotating mass, and further increase acceleration and performance as well.

Upgrading factory gears with stronger alloy gears will prevent part failures in the differential with higher horsepower and race applications. This reduces repair and down time on your high performance vehicle, allowing you more time to focus on winning or enjoying the drive.

The pinion and gear ring convert the direction of force from the driveshaft to the wheels through the perpendicular meshing of gears. They also control vehicle speed through a ratio determined by the number of teeth machined from each steel ring and pinion gear. Depending on the combination, vehicle acceleration can increase while top speed can decrease or vehicle acceleration can decrease with top speed increasing from a gear swap. The ring gear is connected to a ring and pinion differential (either open, limited slip, or other traction design) while the pinion gear is supported in place with bearings and a pinion nut against a yoke via spline to prevent slipping. When determining which diameter ring gear you have, measure across the top of the gear between the furthest points. This will confirm the differential gear diameter to help with the correct parts and identification of your rear axle.

When performing a ring and pinion install, the first step is to remove all of the internal components of the rear axle being worked on. This allows you to inspect other parts like the differential carrier, axles, and other components to plan for a purchase that will include everything you need. To remove the ring and pinion, depending on the rear axle type, the rear cover or third member is unbolted and removed. The brakes are also removed so that the axles can be pulled from the housing. The axles are held in place with retaining clips, which requires removal of the differential cross pin to release the retaining clips. Once the axles are removed, the differential carrier can be removed by unbolting the supports. Be sure to tag which side each support was removed from as well as the number of shims used on each side of the differential carrier. With the differential carrier and ring gear removed, the pinion gear can be retrieved. This is done by removing the pinion nut from the gear. The pinion yoke is then pulled off the gear and it can be carefully pushed inward and removed from the housing. Note the number of pinion shims used for future reference. At this point, the differential housing should be void of any moving parts. A thorough cleaning is the next step. Remember to replace the outer axle bearings and seals at this time as well. Next, make a list of the parts you need for the swap. A differential install kit is strongly recommended to make installation easier with the correct parts including shims, gaskets, seals, all ring and pinion bearings, a ring gear bolt kit, marking compound, crush sleeve, and more. Swap kits are also available that include gear oil and the ring and pinion gear. Inspect any parts that may be reused and determine if you want to upgrade them or reusing them. This includes the pinion yoke, differential carrier, axles, cross pin, retaining clips, etc. Clean and prep the reused parts for installation. Once the replacement parts are in hand and you have everything needed, begin the install in the reverse order of removal of parts. As each differential has different bearing preload, torque specifications, and other steps, be sure to research the correct installation instructions for your specific rear axle. When assembly of the ring and pinion install is complete, you can confirm you have the correct backlash with the marking compound procedure. Then the rest of the parts can be installed and gear oil can be added. Finally, a test drive will confirm the rear is working properly and no unusual noise is being heard.

The differential pinion gear is supported in the housing by an inner and outer bearing and race. The bearings hold it in place and allow it to turn smoothly while staying in place for proper gear meshing. The crush sleeve is located between the bearings and a pinion yoke slides onto the end of the pinion gear splines and through a pinion seal. The yoke is held in place by a pinion nut.

Backlash, which is the side-to-side play between the ring gear and pinion, and pinion depth, which is the front-to-back play between the pinion and the ring gear, must be correct to prevent excessive heat and noise in your rear axle. In addition, pinion and bearing pre-load is just as important for proper operation. If possible, begin with the same number of shims on each side of the differential carrier and pinion gear that were previously used. Otherwise, you will have to start with a number of shims based on an educated guess. The correct order to set up the ring and pinion gears is as follows: pinion depth, backlash, carrier bearing preload, and finally pinion bearing preload. If your differential has a solid spacer or pinion support instead of a crush sleeve, the pinion bearing preload can be set after pinion depth. When setting pinion depth, moving the pinion closer to the ring gear makes the pattern deeper, and shallower when the pinion is moved farther away. A pinion depth tool can help with this as well. When setting backlash, moving the ring gear closer to the pinion reduces backlash, while moving the ring gear farther from the pinion gear increases backlash. Gear marking compound is used to help confirm that the teeth are making the correct contact patch and are not too shallow or deep. In addition, research all of the torque specifications to your specific rear axle for proper operation.

The answer to this question depends on what differential the ring gears are for and what the purpose is for the vehicle. Is the differential a Ford 9", GM 8.5", Dana 60, or something else? This will help to narrow down the possibilities. Is the vehicle going to be on the street or is it for professional drag use only? Some manufacturers focus on street gears, such as Motive Gear, while others focus on drag racing such as Richmond Gear. Every manufacturer that JEGS carries offers high quality gear sets.

A JEGS expert is ready to answer your questions and help you find the differential gears for sale that you need for your next street, race, or custom project.