2019 Ford F-350 Super Duty: Transmission & Axle Ratios

Transmission Gear Ratios

The 2019 Ford F-350 Super Duty was available with two primary automatic transmissions, both 6-speed units from Ford's TorqShift family. The specific transmission depended on the engine choice.

For trucks equipped with the 6.2L gasoline V8, the standard transmission is the TorqShift-G 6-speed automatic.

For the more powerful 6.7L Power Stroke V8 turbo-diesel, Ford equipped the F-350 with the heavier-duty TorqShift 6-speed automatic, designed to handle the massive torque output of the diesel engine.

Available Axle Ratios

The 2019 F-350 offered a wide range of axle ratios to suit various needs, from maximizing fuel economy to heavy-duty towing. The availability of these ratios often depended on the truck's configuration, including the engine, drivetrain (4x2 or 4x4), and specific option packages.

How to Identify Your Axle Ratio

Identifying the specific axle ratio in your 2019 Ford F-350 is a straightforward process. Ford provides this information on the Safety Compliance Certification Label, which is located on the driver's side doorjamb.

To find your axle ratio, open the driver's door and locate the sticker. On this label, you will see a field labeled "AXLE" or "AXLE CODE". The two-digit code in this field corresponds to the axle ratio and differential type installed in your truck from the factory. For example, an axle code of '3L' indicates a 3.55 ratio with a limited-slip differential.

Alternatively, you can find the axle ratio by inspecting the tag on the differential housing itself. This metal tag, bolted to the differential cover, will have the ratio (e.g., "3 55") stamped into it.

Towing vs. MPG Impact

The axle ratio has a significant impact on both towing performance and fuel economy. A numerically higher axle ratio (e.g., 4.30) provides more torque to the rear wheels, which is ideal for towing heavy loads and accelerating from a stop. However, this comes at the cost of fuel economy, as the engine must run at a higher RPM at highway speeds.

Conversely, a numerically lower axle ratio (e.g., 3.31) is better for fuel economy as it allows the engine to operate at a lower RPM on the highway. This reduces fuel consumption but sacrifices some of the truck's raw towing power. A 3.55 ratio is often considered a good "all-around" or balanced option, providing a compromise between towing capability and fuel efficiency.

Common Issues

While the 2019 F-350's driveline is generally robust, some common issues can arise, particularly in trucks that are used for heavy towing or high-mileage applications.

One of the most frequently reported issues is a whining noise from the rear differential, which can be a sign of worn ring and pinion gears. This is often caused by heavy loads or inadequate lubrication.

Another potential issue is carrier bearing failure. The carrier bearings support the differential carrier within the axle housing, and if they fail, you may hear a rumbling or grinding noise that changes with vehicle speed.

For trucks equipped with a limited-slip differential (LSD), the clutch packs within the differential can wear out over time. This can lead to a loss of traction in low-grip situations and may require a rebuild or replacement of the LSD unit.

If you suspect any issues with your F-350's driveline, it's essential to have it inspected by a qualified technician to prevent further damage.

Find a driveline shop on Repairius.