2024 Ford F-350 Super Duty Transmission & Axle Gear Ratios

When spec'ing out or maintaining a heavy-duty truck like the 2024 Ford F-350 Super Duty, understanding the powertrain setup is critical. The transmission internal gearing and the rear axle ratio dictate how effectively the truck can put power to the ground. Whether you are hauling heavy equipment across state lines or utilizing a fleet vehicle for local construction, knowing your gear ratios helps you understand the truck's capabilities, limits, and behavior under load.

Below is the definitive reference for the 2024 Ford F-350 Super Duty transmission and axle gear ratios.

Transmission gear ratios

For the 2024 model year, the Ford F-350 Super Duty utilizes Ford’s heavy-duty 10-speed automatic transmissions. The vast majority of F-350s (equipped with the 7.3L gas V8, the 6.7L Power Stroke diesel, or the High Output 6.7L Power Stroke) use the robust TorqShift 10R140. Trucks equipped with the standard 6.8L gas V8 utilize the slightly lighter-duty TorqShift-G 10R100. Both feature closely matched ratios engineered to keep engines perfectly in their powerbands while towing.

10-Speed TorqShift Automatic (10R140 & 10R100)

Note: The 1st through 10th gear ratios are identical for both the 10R100 and the 10R140. The difference lies in internal clutch pack sizes, planetary gearset durability, and torque converter specifications to handle the massive 1,200 lb-ft of torque generated by the High Output Power Stroke.

Available axle ratios

The differential ratio is just as important as the transmission. Ford offers a wide variety of rear axle ratios for the F-350, depending on whether the truck is a Single Rear Wheel (SRW) or Dual Rear Wheel (DRW) configuration, and which engine is selected.

Note: Non-LS = Open Differential; E-Locker = Electronic Locking Differential; Limited Slip = Mechanical Limited Slip (usually DRW models).

How to identify your axle ratio

If you are buying a used F-350 or need to replace differential components, you must know your exact axle ratio. Fortunately, Ford makes this relatively straightforward.

1. The Door-Jamb Safety Compliance Sticker: Open the driver's side front door and locate the Safety Compliance Certification Label. Look along the bottom row for the word "AXLE." Below or next to it will be a two-digit alphanumeric code. Match that code to the chart above (e.g., "3J" means a 3.55 Electronic Locking differential).
2. The Axle Tag: Crawl under the rear of the truck. Fastened to one of the differential cover bolts, there should be a stamped metal tag. The bottom line of this tag typically starts with the ratio. For example, "3 L 55" indicates a 3.55 Limited Slip, while "3 73" indicates an open 3.73 gear.
3. VIN Decoder: Any Ford dealership parts counter can run your Vehicle Identification Number (VIN) to give you the exact build sheet, including the axle ratio and ring gear size (e.g., Sterling 10.5, Dana M275, or Dana M300).

Towing vs MPG impact

When selecting an axle ratio, you are balancing low-end grunt against high-speed cruising efficiency.

Numerically Lower Ratios (e.g., 3.31, 3.55): Commonly referred to as "tall" gears. Because the driveshaft spins fewer times for every rotation of the tires, engine RPM stays lower at highway speeds. This translates directly to better fuel economy (MPG) and less engine noise during unladen cruising. However, it provides less mechanical leverage when pulling heavy loads off the line.

Numerically Higher Ratios (e.g., 3.73, 4.10, 4.30): Commonly referred to as "short" gears. These multiply torque more effectively, making it much easier for the truck to launch heavily loaded trailers from a dead stop and hold higher gears on steep grades. The trade-off is reduced fuel economy, as the engine must turn at a higher RPM at highway speeds. For a gas-powered F-350 towing heavy loads, a 4.30 gear is highly recommended to keep the engine in its optimal torque band.

Common issues

While the driveline components of the 2024 Ford F-350 are exceptionally durable, extreme towing conditions can cause wear over time. Be aware of the following:

• Ring & Pinion Whine: Heavy towing under excessive heat can break down gear oil. If the gear oil isn't changed at the severe-duty interval, the ring and pinion gears can wear, resulting in a distinct whine on acceleration or deceleration.
• Carrier Bearing Wear: F-350s with long wheelbases feature a two-piece driveshaft supported by a center carrier bearing. Heavy payload cycling and high driveline angles can wear out the rubber isolator and bearing over time, causing shuddering during takeoff.
• Limited-Slip Clutch Wear: For DRW models equipped with a mechanical limited-slip rear end, the internal friction clutches naturally wear out. If you notice only one wheel spinning in low-traction situations, or aggressive binding during tight turns, the clutch packs may need replacement or friction modifier additive.

Need your F-350 differential serviced, gear oil changed, or a full gear-ratio swap? Find a driveline shop on Repairius.