Identifying the rear axle in your vehicle is essential before ordering gears, an axle shaft, or a complete rear end assembly. Here are the most reliable methods.
METHOD 1 — FIND THE AXLE TAG: Most rear axles have a metal tag attached to one of the differential cover bolts or housing studs. This tag will list: • Axle manufacturer or type • Gear ratio (e.g., 3.73, 4.10) • Build date If the tag is present and readable, this is the fastest identification method.
METHOD 2 — LOOK AT THE DIFFERENTIAL COVER AND COUNT BOLTS:
GM: • 10-bolt cover: Most common in light-duty cars and half-ton trucks (8.2", 8.5", or 8.6" ring gear depending on application) • 12-bolt cover: Stronger, found in muscle cars and heavy-duty trucks (8.875" ring gear) Count the cover bolts and note the cover shape — GM covers have a distinctive look for each axle family.
Ford: • 8.8" (10-bolt oval cover): The most common Ford rear end, used in Mustangs and F-150s since the mid-1980s • 9-inch (round cover): The legendary Ford 9-inch, used in older muscle cars and trucks — the cover is round with a removable center section Cover shape is the easiest Ford identifier.
Chrysler/Mopar: • 8.25" (10-bolt): Light duty, common in Jeep and light Ram trucks • 8.75" (10-bolt): Stronger, found in many muscle cars • 9.25" (12-bolt): Heavy duty, common in Ram HD trucks
METHOD 3 — MEASURE THE RING GEAR DIAMETER: If the cover is removed, you can measure the ring gear diameter directly. This gives you the most definitive identification.
METHOD 4 — USE YOUR VIN: If you can't identify the axle from physical inspection, contact us with your VIN at 1-844-XPARTS-1 or support@expediaparts.com. We can look up the factory axle specification for most vehicles.
