* Axle type: Different axle types (e.g., Dana 60, Dana 70, etc.) had different gear ratio options.
* Intended use: Trucks ordered for heavier towing or off-road use often had lower (numerically higher) gear ratios (like 4.10 or 4.56) for more power at low speeds. Trucks intended for better fuel economy on highways might have higher (numerically lower) gear ratios (like 3.54 or 3.73).
To find the gear ratio of *your* specific truck:
1. Check the door sticker (or build sheet if you have one): This sticker often lists the axle ratio.
2. Look at the differential tag: The differential itself usually has a tag stamped with the ratio (e.g., "4.10"). You might need to get under the truck to see this.
3. Calculate it: Jack up one rear wheel, mark a spot on the driveshaft and the tire. Rotate the tire one full revolution and count how many times the driveshaft rotates. The number of driveshaft rotations is the ring gear count (Numerator), and the number of tire rotations is the pinion gear count (Denominator). This ratio is then reduced to its simplest form. (Example: 4 driveshaft rotations and 1 tire rotation = 4:1 or 4.10).
Without access to your truck's documentation or the differential itself, it's impossible to state the gear ratio definitively.
