Direct-fit OE upgrade rear shock for 1999–2016 Ford F-250 and F-350 Super Duty 4WD at stock height. Also fits F-450 Super Duty 4WD (2008–2016). 46mm monotube nitrogen gas design. Asymmetric 16mm upper / 12mm lower eyelet mounts. Made in the USA.
The Bilstein 24-185981 B6 4600 Series Rear Shock Absorber is the 4WD rear shock for the Ford F-250 and F-350 Super Duty — covering both the first-generation (1999–2004) and second-generation (2005–2016) platforms in four-wheel drive configuration. This single part number spans nearly two decades of Super Duty production, making it one of the most wide-reaching applications in the 4600 lineup.
Whether your 4WD F-250, F-350, or F-450 is a work truck, a tow vehicle, or a combination of both, worn rear shocks degrade rear axle stability, increase sway under trailer loads, and reduce the planted composure that defines how capable these trucks feel. The 4600 series restores and improves all of that — more settled highway behavior, better stability under towing and payload loads, and the confident, controlled rear-end performance that Super Duty owners rely on.
Application-tuned for the 4WD F-250, F-350, and F-450 Super Duty rear suspension across two generations
Fade-free rear damping under heavy Super Duty towing and payload loads — consistent performance mile after mile
One part covers 4WD Super Duty from 1999 through 2016 — first-gen and second-gen in a single part number
Designed, engineered, and manufactured in the USA. Backed by Bilstein's limited lifetime warranty
The 24-185981 is for 4WD F-250, F-350, and F-450 Super Duty only. The 2WD Super Duty uses a different rear shock (24-185325) due to its different rear suspension geometry. Verify your Super Duty's drivetrain before ordering. Installing the wrong shock for your drivetrain configuration will result in improper fitment.
Fitment Extends to 2016: Despite the product name listing 1999–2015, multiple sources confirm this shock fits through 2016. Verify fitment for 2016 model year trucks before ordering. F-450 Fitment Starts 2008: The F-450 Super Duty is supported from 2008 onward, not from 1999. F-250 and F-350 run the full 1999–2016 span. Sold Individually: One shock absorber per package. Order qty 2 for a complete rear axle replacement. Stock Height Only: The B6 4600 Series is for stock-height applications only. For lifted Super Duty trucks, see the Bilstein B8 5100 series. Asymmetric Mounts: Upper and lower eyelet sizes differ — 16mm upper and 12mm lower. This is OEM-spec; do not substitute same-size eyelet hardware.
In The Box (Qty: 1 Shock Absorber): • Bilstein 24-185981 Rear Shock Absorber • Blue Protective Boot • Black Rubber Bushings NOT Included: • Mounting Hardware (uses existing OEM hardware) • Second shock (sold individually — order qty 2 for a complete rear pair)
24-186674 — Front B6 4600 for 2005–2016 F-250/F-350/F-450/F-550 Super Duty (pairs with this rear shock for second-gen) 33-028187 — Front B6 4600 for 1999–2004 F-250/F-350/F-450/F-550 Super Duty (pairs with this rear shock for first-gen) 24-185325 — Rear B6 4600 for 1999–2016 F-250/F-350 Super Duty 2WD For a complete stock-height 4WD upgrade, pair with 24-186674 (2005–2016) or 33-028187 (1999–2004) front shocks.
Bilstein Official Product Page Bilstein Technical Support: Website: www.bilstein.com Warranty: Limited Lifetime for original purchaser — B6 4600 series gas pressure shocks. Proof of purchase required. See full terms at Bilstein's website.
The 24-185981 fits the following vehicles at stock ride height with 4WD drivetrain. Note the F-450 starts fitment in 2008, while F-250 and F-350 run the full 1999–2016 span. Sold individually — order two for a complete rear replacement.
⚠️ Fitment cross-referenced across Amazon, Rudy's Performance Parts, ShockWarehouse, Steeda, and Jack-It. 4WD only — 2WD Super Duty requires Bilstein 24-185325. F-450 fitment begins 2008. Confirmed fitment through 2016 by multiple sources despite product name listing 1999–2015. Always verify your specific year and drivetrain before ordering.