2017 Ford F-150 Transmission & Axle Gear Ratios

Transmission gear ratios

The 2017 Ford F-150 offered two primary transmission options: the 6R80 six-speed automatic and the new 10R80 ten-speed automatic. The 10R80 was initially paired with the 3.5L EcoBoost engine, while the 6R80 was standard with other engine options.

6-Speed Automatic Transmission (6R80)

10-Speed Automatic Transmission (10R80)

Available axle ratios

The 2017 F-150 offered a variety of axle ratios to cater to different needs, from fuel economy to heavy-duty towing.

Note: RPO/Axle Codes can vary by specific configuration and build date. Always verify with your vehicle's documentation.

How to identify your axle ratio

For most 2017 Ford F-150 owners, the easiest way to identify your axle ratio is by checking the door-jamb sticker. Look for the "AXLE" code. This code typically consists of two characters. For instance, "L9" would indicate a 3.55 limited-slip axle. If you have an axle tag, which is a metal tag typically bolted to one of the differential cover bolts, it will also clearly state the gear ratio, e.g., "3.55". In some cases, a Ford VIN decoder can provide this information, though the door jamb sticker is usually the most direct method.

Towing vs MPG impact

The axle ratio significantly influences both towing capability and fuel economy. It's a trade-off: a numerically lower axle ratio (e.g., 3.15, 3.31) means the engine operates at lower RPMs at highway speeds, resulting in better fuel economy. However, this also means less torque multiplication, which can hinder towing performance, especially with heavy loads. Conversely, a numerically higher axle ratio (e.g., 3.73, 4.10) provides greater torque multiplication, making it much easier to tow heavy trailers or navigate steep grades. The downside is that the engine will rev higher at a given speed, leading to decreased fuel efficiency. Choosing the right axle ratio depends on your primary use for the truck. If you frequently tow heavy loads, a higher ratio is beneficial. If fuel economy is your top priority and you rarely tow, a lower ratio is more suitable. A "balanced" ratio like the 3.55 often provides a good compromise for mixed-use drivers.

Common issues

While the 2017 F-150 driveline is generally robust, some common issues can arise with the rear axle and differential.

Ring & Pinion Whine: This is often heard as a speed-dependent humming or whining noise, particularly when accelerating or decelerating. It can be caused by improper gear setup, wear, or damage to the ring and pinion gears.

Carrier Bearing Wear: The carrier bearings support the differential carrier within the axle housing. Worn bearings can manifest as a growling or rumbling noise, especially during turns or at certain speeds. Prolonged use with worn bearings can lead to further damage.

Limited-Slip Clutch Wear: If your F-150 is equipped with a limited-slip differential, the clutch packs can wear out over time. Symptoms of worn limited-slip clutches include a chattering or grinding noise during turns, especially tight ones, or a noticeable decrease in traction when one wheel loses grip.

Electronic Locking Differential Malfunctions: While generally reliable, the electronic locking differential can experience issues such as actuator failure, wiring problems, or sensor malfunctions, preventing it from engaging or disengaging properly. This would typically be indicated by a warning light on the dash.

Regular differential fluid changes and inspections can help mitigate these issues and extend the life of your F-150's driveline components.

Find a driveline shop on Repairius.