Hybrid Ford Axle - Ultimate Ford 9-Inch - Killer Drivetrains

Buy the NumbersIf you are in the market to buy a custom-built axle it is important to know the numbers so you don't get stuck with an axle that will need to be swapped out or modified later. Everything from spline counts to gear and locker availability should be considered. Here are some facts to ponder.

Ford 9-inch The 9-inch is one of the few axles that has a removable carrier. It has a ring gear diameter of 9 inches. Common spline counts are 28, 31, and 35. Some expensive custom axles have 40 splines, but you can only get spools to work with these axles. One of the drawbacks of the 9-inch is its low-slung pinion. It sits 231/48 inches below the axle centerline. This can cause driveshafts to bind on short wheelbase vehicles, and the pinion often hits rocks. It's a good idea to have a small skidplate that protects the removable pinion support. Hard impacts can cause it to crack. Ratios ranging from 2.80:1 to 6.50:1 are available. The lowest point on the housing is 531/44 inches from the axle centerline. A high-pinion version of the 9-inch is available from Currie, but limited ratios are available for it (3.31:1 to 4.56:1). The pinion on the high-pinion model is 111/42 inches above the axle centerline, and the ring gear measures 8.8 inches. All other measurements are the same as the 9-inch, and the complete third-members are interchangeable. The high-pinion version is not recommended for vehicles with tires larger than 35 inches or engines pushing more than 500 hp.

Dana 60 The 60 has an integral carrier, making gear swaps a little more time consuming. It has a ring gear diameter of 931/44 inches. Common spline counts are 30 and 35. An aftermarket 40-spline version is available. The major drawback of a 60 is its weight. The pinion sits 111/48 inches below the axle centerline. That's 111/44 inches higher than a 9-inch. Many wrongly believe that the 60 hangs precariously low. The lowest point is 6 inches below axle centerline, only 11/44 inch lower than the 9-inch and 31/44 inch lower than a Dana 44. Ratios from 3.54:1 to 7.17:1 are available. A reverse-rotation high-pinion version is available in ratios from 3.54:1 to 5.13:1. The pinion sits 111/48 inches above the axle centerline on the high-pinion model. All other measurements are the same as the standard Dana 60.