Revolution Gear & Axle Ring & Pinion Set for GM 8.5" & 8.6" 10-Bolt (4.10 Ratio, Face Hobbed)

This is a Revolution Gear & Axle ring and pinion set for the GM 8.5" and 8.6" 10-bolt rear, cut in a 4.10 ratio. It fits the 10-bolt axle family found under a huge range of GM half-ton trucks, SUVs, and vans, so it's identified by axle rather than a single vehicle. If your rear cover has 10 bolts and the ring gear measures 8.5" or 8.6", this is the gear family you're working with.

The set uses a face-hobbed (also called 2-cut) cutting process followed by lapping, the same approach the OE brands use. Face-hobbed gears carry equal tooth height from heel to toe, run quieter, and handle more load than traditional face-milled gears. The pinion is 30-spline, the ring gear bolt thread is 7/16", and the gears are made from 8620 steel and heat treated for strength. This 4.10 ratio uses a 2.56/2.73 carrier break.

A 4.10 re-gear is the common move after stepping up to larger tires on a GM 10-bolt truck or SUV. Bigger tires raise your effective gear ratio and rob low-end response and towing grunt; dropping to 4.10s restores that torque at the wheels and gets the engine back into its happy RPM range on the highway.

This is a gear set only. It does not include bearings, shims, a crush sleeve, a pinion seal, or any carrier or locker – those are sold separately. Before ordering, verify your carrier matches the 2.56/2.73 carrier break for this ratio. Setting up a ring and pinion correctly takes the right tools and experience, so professional installation is strongly recommended.

Pair this gear set with a Revolution master install kit for the GM 8.5/8.6 and you have everything needed for a quiet, durable rebuild backed by a 2-year warranty against manufacturing defects.