The Bilstein B6 4600 rear shock for the 2004 Ford F-150 Lariat 4WD is a 46mm gas-pressure monotube damper. Its nitrogen-infused design uses a floating dividing piston to separate the gas and oil, which the manufacturer says provides consistent, fade-free performance. Bilstein's patented digressive valving reacts to changing surface conditions, which the manufacturer says gives a stable, controlled ride. Buyers searching for a 2004 F-150 Lariat 4WD rear monotube upgrade, a 46mm B6 4600 rear shock, or a gas-charged rear damper for towing will find this unit fits that profile.
Compared with stock, the main case for this shock is control and durability. One owner on a user forum who swapped in rear Bilsteins described them as far better than the factory units in every respect. The manufacturer adds that the high gas pressure supports a longer service life even when pulling trailers or driving off-road. Because no spring change is required, the upgrade keeps the factory spring rate, so you get better damping without changing ride height.
Confirm fitment against the manufacturer's application guide for your exact cab, drivetrain, and suspension before ordering, since rear applications vary. Owners on user forums call the rear swap a straightforward bolt-on job. The manufacturer's mounting instructions still call for special tools and expert knowledge, so a professional suspension technician is the safer route if you lack a lift or shop experience.
The manufacturer states that no spring change is needed, and the factory spring can be reused with this unit.
The manufacturer's installation guidance says all Bilstein products should be fitted by a professional automotive suspension technician, because the work requires special tools and expert knowledge.
Owners on user forums who have made this swap report a clear improvement over the original rear dampers in control and ride quality.
Owners on user forums describe the rear as an outboard-mounted, bolt-on replacement, so it is one of the more approachable suspension jobs on this truck. The manufacturer's installation guidance warns that improper installation will cause permanent damage to the shock, and advises replacing shocks as a pair when replacing other brands. Bilstein's guidance also notes that its gas-filled units are highly pressurized, so handle them with care. Use the manufacturer's torque specifications and confirm them with the official install sheet before tightening.
