Dynatrac 80 Pro Series Axle Review

    The End Of Axle Breaks

    Jerrod JonesPhotographer, Writer

    Welcome, children. Today you will be schooled on the end-all steering axle you can bolt under your 4x4. And don't even think about letting images of Dana 60 axles pop in your heads. Though the Dana 60 axles have proved time and again that they can stand up to almost any abuse even a 44-inch tire can dish out, like anything within the physical world they have their limits. And since the industry has decided to up the ante with 46-inch Baja Claws, 49-inch Iroks, and 52-inch Michelin special implement tires, a few people have found the limits of Dana 60 axles. We can make them with 1.71-inch 40-spline axleshafts, beef up the housings for less gear deflection, put bigger knuckles on and giant U-joints in the axles, but we can't change that ring-and-pinion size. The next logical step would be a Dana 70 housing with a 10 1/2-inch ring gear, but you're still stuck with a 1.25-inch-diameter pinion shaft (the same as a Dana 60), so forget that idea.

    So who you gonna call when you're a '60 axlebuster? Dynatrac, that's who. We're pleased to help introduce Dynatrac's new one-up in front axle beef; the Pro Series 80. Check it out. It might be just what your 4xpharmacy prescribes.

    Dana 80s have been around for quite a while. There are already lockers available, and they even came as factory equipment underneath some trucks. But stock Dana 80s came with either 35-spline or 37-spline axleshafts. To get the required 40-spline axles in, Dynatrac worked with Eaton (which now owns Detroit Locker) to get a specially broached 40-spline Detroit Locker. Other than the side gears having an enlarged inner shaft diameter, the Detroit Locker is unchanged from its original Dana 80 form.

    A 40-spline axleshaft (right) has a 1.71-inch diameter. A 35-spline axleshaft (left) has a 1.50-inch diameter. Stock Dana 60s come with either a 30-spline 1.31-inch axle or a 35-spline axle. Stock Dana 70s come with a 35-spline axle. Stock Dana 80s come with a 35- or 37-spline 1.60-inch axle. But Dynatrac's Pro Series 80 comes with a 40-spline axleshaft that makes it larger than almost anything else on the market.

    From left to right are the Dana 60, Dana 70, and Dana 80 ring-and-pinion gearsets. The Dana 60 has a 9 3/4-inch ring gear and 1.25-inch pinion shaft diameter. The Dana 70 has a 10 1/2-inch ring gear, but the pinion shaft diameter is still 1.25 inches, the same as in a Dana 60. The real step up in ring-and-pinion strength is the Dana 80 gearset. The ring gear measures a robust 11 1/2 inches, while the pinion shaft diameter takes up 1.625 inches in the pinion bearing.

    Dynatrac's 40-spline Competition Alloy axleshafts are fitted with CTM U-joints, and these are no exception. The 1480-series CTM U-joints will soon connect these inner and outer axleshafts in the custom-built housing.

    Dynatrac cast its own special Dana 80 centersection. It's a low-pinion design, and is reinforced in multiple places to not let the ring gear deflect from the pinion. When you see how big this pumpkin is in real life, you can truly see why this is the end in axle beef. This housing takes an 11 1/2-inch ring gear and makes the 40-spline axleshafts that enter it look almost puny.

    At each pinion yoke, a 1410 U-joint transfers power from the spinning driveshaft. Should you ever put the almost unimaginable amount of stress it would take to break this axle, it will most likely break at the yoke's U-joint, instead of breaking the 1480 steering U-joints and taking the axleshafts with it.