Ring and Pinion Gears

How Ring and Pinion Gears Work

Ring and pinion gears turn driveshaft rotation 90 degrees and send it to the wheels, multiplying torque along the way. They're the main differential gears in the axle, and you'll find them alongside other differentials and rear-end components. The small pinion gear spins with the driveshaft and drives the larger ring gear.

The ring gear bolts to one of the differential carriers, which splits torque between the left and right axles. Your gear ratio equals the ring gear tooth count divided by the pinion tooth count. A 41-tooth ring gear with an 11-tooth pinion gives you a 3.73:1 ratio.

That means the driveshaft turns 3.73 times for every wheel revolution. The two gears are made and run in as a matched pair, so you always replace them together. Because the carrier, bearings and gears all share the housing, a gear swap is often part of a larger rear-end rebuild.

How to Choose a Gear Ratio

Choose a gear ratio based on tire size, transmission and overdrive gearing, engine powerband and how you drive. A numerically higher ratio gives you more acceleration but raises engine RPM at cruise. A numerically lower ratio drops cruise RPM and gives up some launch.

Common ratios in this category and their typical uses include:

• 3.27 and 3.55: daily driving and highway cruising at lower engine RPM
• 3.73: a street-performance balance of launch and highway manners
• 4.11: towing, heavy-duty trucks and street/strip cars that need more launch
• 4.88 and 5.13: drag racing, rock crawling and larger off-road tires

If you're moving to taller tires, you'll usually need a numerically higher ratio to restore lost acceleration. Plan to recalibrate your speedometer after any gear ratio change. For formulas and charts, read our guide on how to choose the correct rear gear ratio before you order.

Ring and Pinion Gear Sets by Axle Type

Ring and pinion gear sets are axle-specific, so confirm your housing first. Ring gear diameter, bolt pattern and spline count vary by axle. Start with our guide on how to identify a domestic differential axle assembly.

Axle types with gear sets listed here include:

• Ford 8.8 ring and pinion sets in 3.27 and 4.88, plus Super 8.8 3.55 sets for 2015-2024 F-150 and Mustang
• Ford 9.75 sets in 3.55 and 3.73
• Ford 9-inch gears, including 35-spline sets, plus Ford 9.5 sets in 4.11
• GM 10.5 14-bolt 4.11 sets for 1970-2015 Chevrolet and GMC trucks
• AAM 11.5 4.11 sets for 2001-2016 Chevy, GMC and Ram 2500/3500 trucks
• Chrysler 9.25 sets in 3.55
• Dana 44 ring and pinion sets in 3.73 and 5.13, including Jeep Wrangler JL and Gladiator

Shop Ford 9-inch third members if you want a drop-in center section. Our Ford 9-inch rear end and axle guide covers case and spline details.

Ring and Pinion Gear Brands We Carry

You can shop ring and pinion gears from several drivetrain brands and narrow results with the brand and product line filters. Brands in this category include Motive Gear, Yukon Gear and Dana Spicer. Compare ratios, materials and fitment side by side before you pick a set.

Use the vehicle selector with the brand filter to see only the sets that fit your axle.

Some listings show how brands cover specific builds. Richmond Gear offers a Ford 9.5-inch 4.11 set, and Excel offers a Dana 60 3.54 set. Speedmaster lists a Ford 9-inch 35-spline 3.50:1 set made from 8620 steel.

For a one-box rebuild, JEGS-brand complete differential installation kits include a version for Ford 9-inch 3.06-inch cases. Quick-change gear sets are also listed for quick-change rear ends. The material filter helps you compare gear steel, and the position filter separates front and rear sets.

Installation Kits, Bolts and Supporting Parts

A ring and pinion installation kit gives you the parts to set up new gears in one order. Kits typically include bearings, races, shims, seals and hardware. Setup requires correct pinion depth, pinion bearing preload and ring gear backlash, confirmed with a gear marking pattern.

Crush sleeves or solid spacers set pinion preload, depending on the axle design. If you're unsure about setup, a gear shop can handle the final checks.

Ring gear bolts and spacers matter too. Strange Engineering ring gear bolts are listed here, along with spacers for certain gear and carrier combinations. Torque every bolt to the gear maker's spec during assembly.

You'll also need fresh gear oil and a cover gasket or sealant. If your stock cover is damaged or you want easier fill and inspection, browse our differential covers. When your parts list is ready, add your vehicle above and shop ring and pinion gears that fit your axle.