2021 Ford F-350 Super Duty
Vehicle Specs & Maintenance Data
The 2021 Ford F-350 Super Duty maintenance specs on this page cover the key fluids, torque values, and wear items you need for routine service. Use these numbers as a quick reference when performing oil changes, tire rotations, brake jobs, and other scheduled maintenance on your Ford F-350 Super Duty.
For oil changes, the 2021 Ford F-350 Super Duty takes 5W-30 Full Synthetic motor oil with a capacity of 7.5 quarts. Brake fluid type is DOT 3, the recommended coolant is Motorcraft Gold (OAT), and transmission fluid is Mercon LV. Always use the manufacturer-recommended fluids to maintain warranty coverage and engine longevity.
When mounting wheels on the Ford F-350 Super Duty, torque the lug nuts to 150 ft-lbs using a calibrated torque wrench. Over- or under-torquing can lead to warped brake rotors or loose wheels. Re-torque after 50 to 100 miles on newly installed wheels.
Owners of the 2021 Ford F-350 Super Duty have reported 5 common issues including "6.7L Power Stroke CP4 Fuel Pump Failure", "Diesel Exhaust Fluid (DEF) System Failures" and "Steering Wander and Death Wobble". Scroll down to the Diagnostics tab for detailed descriptions, solutions, and estimated repair costs.
Specifications on this page are compiled from multiple publicly available sources including manufacturer documentation, NHTSA data, and automotive databases. Always cross-reference with your owner's manual or official factory documentation before purchasing parts or performing any service.
The 2021 Ford F-350 Super Duty uses 5W-30 Full Synthetic motor oil (7.5 qt capacity), requires lug nuts torqued to 150 ft-lbs, takes DOT 3 brake fluid.
Manufacturer-recommended maintenance schedule for the 2021 Ford F-350 Super Duty. Always verify intervals against your owner's manual.
Enter a diagnostic trouble code to see causes, symptoms, and fixes for the 2021 Ford F-350 Super Duty.
Common problems reported by 2021 Ford F-350 Super Duty owners, with recommended fixes and estimated repair costs.
6.7L Power Stroke CP4 Fuel Pump Failure
The Bosch CP4.2 high-pressure fuel injection pump on the 6.7L Power Stroke diesel can fail catastrophically, sending metal debris throughout the entire fuel system. Contaminated fuel damages the injectors, fuel rails, fuel lines, and fuel tank. The failure often occurs without warning and results in immediate engine shutdown.
Replace the CP4.2 pump and flush the entire fuel system, including injectors, fuel rails, lines, and tank. The repair is extremely expensive. Many owners install a lift pump or fuel filtration system as preventive measures. Some aftermarket companies offer CP4 disaster prevention kits. Ford has faced class-action litigation over this issue.
Est. Cost: $8,000 - $12,000 for complete fuel system replacementDiesel Exhaust Fluid (DEF) System Failures
The DEF injection system is prone to multiple failures including DEF quality sensor errors, DEF heater faults, SCR catalyst inefficiency codes, and injector clogging. When the DEF system enters a fault state, a 5-mph limp mode countdown begins after a set number of miles, eventually making the truck nearly undrivable.
Diagnose with a scan tool to identify the specific DEF component failure. Common repairs include replacing the DEF quality sensor, DEF heater element, DEF injector, or the entire DEF tank assembly. Ford issued multiple TSBs addressing DEF system faults. Use only API-certified DEF fluid.
Est. Cost: $300 - $800 for sensors/heater; $1,000 - $2,500 for DEF tank assembly; $500 - $1,200 for injectorSteering Wander and Death Wobble
The Super Duty is prone to a violent front-end oscillation known as 'death wobble' that occurs after hitting a bump at highway speeds. The steering wheel shakes violently and uncontrollably, requiring the driver to slow down significantly to stop the oscillation. Worn steering and suspension components are the root cause.
Ford issued TSB 19-2305 addressing Super Duty front-end shimmy. Replace the steering damper with a Fox or Bilstein heavy-duty unit. Inspect and replace worn ball joints, tie rod ends, track bar, and track bar bracket. A loose track bar bracket bolt is the most common single cause. Have the front end aligned after repairs.
Est. Cost: $100 - $300 for steering damper; $1,000 - $3,000 for complete front-end rebuildTurbocharger Wastegate Actuator Failure
The variable geometry turbocharger on the 6.7L Power Stroke can develop wastegate actuator problems, causing overboosting, underboosting, or turbo surge. Symptoms include loss of power, excessive black smoke, check engine light with boost pressure codes, and a whistling or squealing sound from the turbo area.
Replace the turbocharger wastegate actuator or the entire turbocharger assembly if the internal vanes are damaged. Clear the DTC codes and perform a turbo relearn procedure. Ford issued TSBs addressing turbo calibration issues. Ensure the exhaust back-pressure sensor is functioning correctly.
Est. Cost: $500 - $1,000 for actuator; $2,000 - $4,000 for turbo replacementRear Axle Seal Leak (DRW Models)
Dual rear wheel (DRW) F-350 models develop rear axle hub seal leaks that allow gear oil to seep onto the brakes and wheels. The leak is visible as an oily film on the inside of the rear wheels. Contaminated brake pads and rotors lose braking effectiveness and create a fire risk.
Replace the rear axle hub seals on the affected side. Inspect the rear brake pads and rotors for oil contamination; contaminated pads and rotors must be replaced, as they cannot be cleaned. Check the differential fluid level and top off with 75W-140 synthetic gear oil.
Est. Cost: $300 - $700 per side for seal; $400 - $800 for brake replacement if contaminated