How do I find my Ford axle ratio?
Your Ford axle ratio is the gear ratio inside the differential that determines how far the driveshaft must turn for each wheel revolution. It is typically printed on a rear-axle tag, listed on the vehicle’s window sticker or build sheet, or available by decoding the vehicle’s VIN. If those sources aren’t accessible, you can estimate by counting gear teeth as a last resort.
Where to look for the axle ratio
There are several reliable places to check for the exact axle ratio. Start with the easiest and most authoritative source first.
- Rear differential tag: Look on the differential housing (often on the driver's side, near the top). The tag will typically show "AXLE" along with a number such as 3.55 or 3.73, representing the ratio (for example, 3.55:1).
- VIN-based or build documentation: If you have access to the vehicle’s VIN, the official build data or dealer documentation often lists the axle ratio under drivetrain or AXLE. This can also appear on the window sticker for a new vehicle or the original build sheet.
- Window sticker or build sheet: For new or certified-used Ford vehicles, the order sheet/window sticker typically lists the axle ratio in the drivetrain section (for example, "AXLE: 3.55").
- Dealership or Ford owner resources: If you can’t read the tag or sticker, a Ford dealer can pull the axle ratio from your VIN using Ford’s internal systems.
Knowing the exact axle ratio helps with gear-swapping, fuel economy estimates, and towing calculations. If none of these options are accessible, move to the next section for other verification methods.
How to read or verify the axle ratio
Once you’ve located a potential source, use these steps to confirm the ratio and avoid misreading codes or labels.
- Reading the differential tag: If the tag reads "AXLE 3.55," that's the ratio 3.55:1. Some tags include the ratio with a suffix or a code; read the numeric portion carefully and note whether the value is a ratio (3.55) or a code that requires cross-reference.
- Reading the rear cover stamping: Some older or utility Ford models stamp the ratio directly on the differential cover or housing; you may need to wipe and inspect the stamping. Look for a number such as "3.55" or similar to identify the ratio.
- Using the VIN decoder: With the VIN, check the drivetrain section for "Axle" or "Axle ratio." Ford's official VIN decoder or a trusted service provider can return the exact ratio associated with your VIN. If the decoder does not show it, contact the dealer for a precise figure.
- Counting teeth as a last resort: If you must, you can remove the differential cover and count teeth on the ring gear and pinion gear. Divide the ring gear teeth by the pinion teeth to get the ratio (e.g., 44 ring teeth / 14 pinion teeth ≈ 3.14). Note that this approach requires mechanical skill and proper safety.
Be aware that some Ford models have separate front and rear axle ratios, especially in all-wheel-drive or four-wheel-drive configurations, which can differ. Verify both axles if your vehicle has more than one drive axle.
Common Ford axle ratio values
Ford has offered a range of axle ratios across different models and production years. The most common rear-axle ratios you’re likely to encounter include the following. Some models also offer multiple option levels per engine/transmission combo.
- 2.73
- 3.31
- 3.55
- 3.73
- 4.10
- 4.30
Note that the exact availability depends on model year, trim, engine choice, and drivetrain (2WD vs 4WD), so always verify with the tag, sticker, or VIN data as described above.
Model-specific notes
Some Ford families display different patterns. For example, F-Series trucks often have a selectable range of axles based on axle code, while passenger cars like the Fusion, Focus, or Mustang may have fewer options. If you commute with a blend of towing and highway driving, you might find different rear-axle gear options across trims; always confirm the correct ratio for your exact vehicle, not just your model year.
Summary
The axle ratio is the drivetrain gear ratio in your Ford's differential and is usually printed on the rear-axle tag, listed on the window sticker/build sheet, or retrievable via the VIN. If needed, you can verify by counting gear teeth or consulting a dealer. Using the correct axle ratio is important for accurate towing calculations, gearing, and fuel economy planning.
