Ford Racing M-4209-88355A Super 8.8" IRS Ring and Pinion Set 3.55:1 Ratio

The Ford Racing M-4209-88355A is a precision-engineered 3.55:1 ratio ring and pinion gear set designed specifically for 2015-2025 Mustang Super 8.8-inch Independent Rear Suspension (IRS) center sections. Made in the United States at Ford's Sterling Axle Plant, this OEM-quality gear set delivers superior surface finish, hardening, and manufacturing consistency for the strongest and quietest performance on the market.

Key Features:

• 3.55:1 gear ratio with 39 ring gear teeth and 11 pinion gear teeth
• Black oxide coating for superior corrosion resistance
• Includes OEM crush sleeve and pinion nut
• 30-spline pinion shaft with 2.010-inch diameter
• 8.8-inch ring gear diameter with 10 bolt pattern
• Race-proven design used by championship road racing and drag racing teams

What's Included:

• 3.55 ratio ring and pinion gears
• OEM crush sleeve
• Pinion nut

Important Installation Notes:

• Requires M-4210-B3 Mustang 8.8-inch ring gear and pinion installation kit (sold separately)
• Will not fit models with factory 3.15:1 gears without changing the differential to M-4204-MT or M-4204-M
• Requires aftermarket calibration if vehicle is not originally equipped with this gear ratio

The 8.8-inch rear end has been the standard in Ford performance since its introduction in the Mustang in 1986, and Ford Racing continues to be the manufacturer of choice for serious performance builders. This gear set is engineered, manufactured, and tested to meet the demanding requirements of competition and high-performance applications.

Competition Use Only: This part is designed and intended for competition use only or off-highway use only. It should not be installed on a vehicle driven on public roads and highways. Installation on street-driven vehicles may violate U.S. and Canadian emissions regulations.