6-Inch Lift Kit with M1 Shocks for Ford Super Duty 4WD (2017–2022), Part 55640

6-Inch Lift Kit with M1 Shocks, fitment-checked

Rough Country 55640 is a 6-inch lift kit for 2017–2022 Ford Super Duty 4WD trucks, built around front coils, radius arm drop and upgrade brackets, fabricated 4.5-inch rear blocks with U-bolts, a transfer case clocking kit, and two pairs of M1 monotube shocks. The exclusion list rules out dually trucks, gas engines, manual-shift transfer cases, 4-inch rear axle tubes, factory contact overload springs, Tremor-equipped trucks, and F-350 models. Verify your configuration first.

This 6-inch lift kit for the 2017–2022 Ford Super Duty 4WD covers XL, XLT, Lariat, King Ranch, Platinum, and Limited trims listed in the fitment section. Front coils raise ride height while the radius arm drop brackets reset caster to keep steering behavior close to stock, and the fabricated rear blocks are shaped to resist axle wrap. Two pairs of M1 monotube shocks handle damping front and rear. Read the exclusion list closely (it covers dually, gas-engine, manual-shift transfer case, and Tremor trucks) then work from the downloadable Rough Country installation guide. Shipping weight: 271.0 lb.