F-250 / F-350 2017–2019 LoadLifter 5000 Ultimate Helper Spring Kit | Air Lift 88399

Get LoadLifter 5000 support plus an internal jounce bumper for a smoother loaded ride. The Air Lift 88399 LoadLifter 5000 Ultimate kit adds up to 5,000 lbs of adjustable rear load support on 2017–2019 F-250 and F-350 Super Duty 4WD trucks. It helps keep the truck level when towing a fifth-wheel, running a gooseneck, or hauling a heavy bed load. The closed-cell urethane foam jounce bumper inside each air spring absorbs shock, reduces harsh jarring, helps prevent bottoming out, and lets you safely run with zero air pressure if a bag loses air. Air pressure is fully adjustable from 5–100 PSI.

Key features

• Up to 5,000 lbs of load-leveling capacity (never exceed the truck’s GVWR)
• Exclusive internal jounce bumper for three-stage ride comfort and bottom-out protection
• Maintenance-free design that can safely run at zero PSI
• Adjustable from 5–100 PSI for empty, partial, or max-load conditions
• 2-ply fabric-reinforced rubber bellows built like a tire
• Upper and lower roll plates protect the bags and help increase capacity
• Replaces the factory jounce bumper that is often removed when adding air springs
• Under-frame, no-drill installation on most applications
• Works with most side-mount fifth-wheel and factory in-bed hitch systems
• Fits both single rear wheel (SRW) and dual rear wheel (DRW)
• Quick-connect air fittings with included air line and Schrader valve
• Limited lifetime warranty

Fitment

• 2017–2019 Ford F-250 Super Duty 4WD
• 2017–2019 Ford F-350 Super Duty 4WD
• Also fits many 2017–2019 Ford F-450 Super Duty 4WD pickups
• Compatible with 6.7 Powerstroke diesel and gas engines
• Rear axle / factory leaf springs

Fits trucks with no fifth-wheel hitch and most side-mount fifth-wheel or factory in-bed hitch applications. Does not fit 2WD models or cab & chassis trucks.

What’s in the box

• Pair of LoadLifter 5000 Ultimate air springs with internal jounce bumpers
• Upper and lower roll plates
• Vehicle-specific mounting brackets and hardware
• Air line, fittings, and Schrader fill valve
• Illustrated installation manual

Notes & specs

• Compressor, in-cab gauges, and wireless controllers are not included
• Pair this kit with an Air Lift WirelessONE, LoadController, or similar onboard air system if you want to adjust pressure from the cab
• Brand/part number: Air Lift LoadLifter 5000 Ultimate 88399
• UPC: 729199883996
• Position: rear
• Capacity: up to 5,000 lbs
• Pressure range: 5–100 PSI
• Internal jounce bumper: yes
• Can safely run at 0 PSI
• Mount: under-frame
• Drilling: typically none
• Install time: about 1–2 hours
• Replacement spring: Air Lift 84293
• Kit weight: about 35 lbs
• Warranty: limited lifetime

Most 88399 kits bolt on with no frame drilling and install in roughly 1–2 hours with basic hand tools. Route the included air line to a convenient fill point at the bumper, bed, or license-plate area. Always set pressure for the load you are carrying and do not exceed the vehicle manufacturer’s GVWR. If your 2017–2019 F-250 or F-350 4WD squats under a trailer or bed load, the Air Lift 88399 LoadLifter 5000 Ultimate kit adds 5,000 lbs of adjustable support plus an internal jounce bumper for a safer, smoother ride.