What axle does my F-150 have?
Your F-150’s axle configuration depends on its year, drivetrain, and trim. In most recent models, the front suspension is independent and the rear axle is an 8.8-inch ring-gear unit, while older or heavier-duty configurations could use a different rear axle size. To know for sure, check the vehicle’s labels, VIN, or the differential itself.
This article explains how to identify your exact axle, what to expect on different model years, and how to verify the information using factory labels, VIN decoding, or a quick look at the differential housing.
How to identify your F-150’s axle
Use these steps to determine the axle on your truck. Each method helps confirm the exact size or code without guessing.
- Check the door jamb data label: look for entries labeled Axle and Axle Ratio or a numeric code that corresponds to Ford’s axle options for your year and trim.
- Decode the VIN: use Ford’s official VIN decoder or a reputable third-party service to extract the axle code or rear gear ratio associated with your exact build.
- Inspect the differential housing: remove a small access plug or look at the stamping on the rear diff cover for the model (e.g., 8.8" or 9.75" ring gear designations) and the gear ratio etched on the tag.
- Measure or compare the ring gear diameter: an 8.8" rear axle is smaller than a 9.75" unit; this can be confirmed by the number of bolts on the differential cover and the overall housing size.
- Consult the owner’s manual or dealership records: sometimes the build sheet or window sticker lists the exact axle configuration by code.
With these checks, you’ll be able to confirm whether your F-150 uses the standard 8.8" rear axle, a 9.75" unit, or another configuration that may appear on special editions or older models.
Common axle configurations in Ford F-150 history
Understanding typical configurations helps set expectations, but the exact setup varies by year and package. The following outlines what is commonly found, along with how to verify your specific truck.
- Front axle: most F-150s employ independent front suspension (IFS) in contemporary builds, which means there isn’t a solid front axle housing with leaf springs. This setup improves ride quality and load handling.
- Rear axle: the 8.8-inch ring-gear rear axle is the standard for many F-150 models across several generations, with various gear ratios offered depending on engine and drivetrain choices.
- Older or special editions: some earlier F-150s and certain heavy-duty or limited-run versions used a larger 9.75-inch rear axle, which was less common on the most recent models.
- Gear ratios: the axle ratio varies by engine and trim and is typically in the range of about 3.31 to 4.10, with different configurations for 2WD vs. 4WD and for highway vs. off-road use.
If you’re shopping for parts or planning a modification, confirming the exact axle size and ratio is essential, as it affects gearing, gearing-related parts, and compatibility with accessories.
Summary
To know your F-150’s axle, start with the door data label and the VIN, then verify with the differential housing and, if needed, a dealer or VIN decoder. Most recent F-150s use independent front suspension and an 8.8-inch rear axle, while some older or specialty models used a 9.75-inch rear axle. Gear ratios vary by engine and package, so check the exact code to ensure accurate parts matching. A quick, labeled glance at the axle or a reliable VIN decode will usually provide a definitive answer.
How do I know which axle my truck has?
The most accurate differential identification is provided by the bottom line of the tag number or axle tube stamp.
How do I tell what axle my F150 has?
To find what axle your F-150 has, check the "AXLE" code on the Safety Compliance Certification Label inside the driver's side door jamb to find the ratio, or look for the differential type (Ford 9.75" or Ford Super 8.8") by visually inspecting the differential cover.
Method 1: Use the door jamb sticker
- Open the driver's side door: and find the label on the door jamb or the door itself.
- Locate the line that says "AXLE": underneath the bar code.
- Find the two-digit code: that follows "AXLE".
- Cross-reference the code: with a chart to determine your axle ratio. For example, 3L is a 3.73 ratio with a limited slip differential, L5 is a 3.15 ratio, and L3 is a 3.31 ratio, notes More Power Tuning and YouTube.
Method 2: Visually identify the differential type
- Locate your F-150's rear differential, which is the round housing at the center of the rear axle.
- Inspect the shape of the differential cover. The two common options for modern F-150s are the Ford 9.75" and the Ford Super 8.8".
- Visually distinguish them. The 9.75" has a more rounded shape, while the Super 8.8" is also rounded but often has a slightly different, more "modern" look. For precise identification of specific axle sizes like the Super 8.8" vs. the older 8.8", you may need to look up the bill of materials or check specific features of the cover itself.
How do I know if I have 28 or 31 spline axles?
Inspect the center of the axle end: Look for a depression or marking in the center of the axle hub. 28-spline: You will likely see a rectangular depression. 31-spline: You will likely see a small round depression in the center, with two additional small holes or depressions located outside of it.
Does the VIN number tell the axle ratio?
Yes if it's not been molested. If you bought it used and there is any indicator that the covers have been removed from the truck you need to pull them and visually verify the ring and pinion for the correct gear ratio.
