Ford 8.8 Ring and Pinion Gear Set 3.73 Ratio F8.8-373A

This is the Motive Gear F8.8-373A ring and pinion set, a 3.73:1 gear set for the Ford 8.8-inch rear axle. The 8.8 is the 10-bolt rear that lives under a huge span of Ford, Lincoln, Mazda, and Mercury vehicles from 1980 to 2020, including the F-150, Mustang, Ranger, Explorer, Crown Victoria, E-150, F-250, and Thunderbird. You open this box when you are regearing to recover the acceleration and towing grunt lost after going to a taller tire, or when you are replacing a howling or spun original gear set.

The gears are cut from 8620 alloy steel and heat treated for wear resistance under load. The pinion is the 30-spline design, and the set is machined for an OE-style fit so it drops into the factory 8.8 housing with the correct pattern when it is set up right. Going to 3.73 is a common step up from the factory 3.31 or 3.55 to sharpen throttle response and hold gears better under a trailer, without hurting highway manners the way a deeper 4.10 or 4.56 can. It cross-references to Richmond Gear 49-0104-1, EXCEL F88373, and Motive Gear F8.8-373.

This is the gear set only. Plan on a full install kit to do the job: carrier and pinion bearings and races, the crush sleeve or a solid spacer and shim pack, a new pinion seal, and ring gear bolts. Set pinion depth to the marking etched on the pinion head, run backlash in the 0.008 to 0.010 inch range, load the carrier bearings to spec, and check your gear pattern before you button up the cover. Gear set weight is about 11.8 lb. Ships from the USA; handling in 1-2 business days.