8.8 IRS Loaded Differential Housing w/3.55 gears

Loaded differential housing for Mustang IRS Fits 2018-2024 Mustang  Fits 2015-2017 Mustang (see technical notes below) Iron housing with aluminum cover Includes 3.55:1 ratio gear set M-4209-88355A and Traction-Lok differential M-4204-M     Custom calibration required for speedometer and shift corrections  Original Equipment on 2019 Mustang GT    Note-on 2015-2017 Mustang, pinion flange change may be necessary; comes with pinion flange with 93mm bolt circle and 110mm driveshaft pilot installed. For applications that require 95mm bolt circle and 113mm driveshaft pilot, use FR3Z-4851-B pinion flange, available through Ford dealer