Revolution gear Toyota 8" 4Cyl 4.56 ratio gear sets are made from top quality 8620 steel and are precision heat treated to OEM specifications, making for the best aftermarket gears available. All revolution ring and pinion sets are backed by an industry leading 2 year warranty against defects. Revolution gears are also double, and in some cases triple lapped for flawless setup, smother running and longer life. With products that have been street, off road and race proven for more than a decade, you can count on Revolution Gear & Axle products to be the best aftermarket parts available.