USA Standard Master Overhaul Kit For The Dana 80 Diff (4.125in OD Only)
The Dana 80 sits under the heaviest one-ton dually and F-450 class trucks, and when it starts to whine under load, drips from the pinion seal, or needs new gears for a towing ratio, every bearing in it should be replaced at once. This USA Standard Gear master overhaul kit, part number ZK D80-A, carries the bearings, races, seal, shims and hardware for a Dana 80 rear axle that uses the 4.125-inch outside-diameter pinion bearing.
The Dana 80 is a full-floating rear axle with an 11.25-inch ring gear and 35- or 37-spline axle shafts. Because the axle shafts only drive the wheels and the hubs carry the truck, the differential bearings take the full torque of a big diesel or V10 pulling a trailer. The pinion runs on two large tapered bearings, and its depth and bearing preload are set with shims rather than a crush sleeve, which is why the manufacturer packs this kit with a complete shim set and leaves the crush sleeve out. The carrier side bearings, also shimmed, set backlash and carrier preload. Once any of these bearings wear, pinion depth and backlash drift and the gear teeth begin to howl and wear unevenly.
According to the manufacturer, ZK D80-A includes Koyo carrier bearings and races, Koyo pinion bearings and races, the pinion seal, a complete shim kit, ring gear bolts, the pinion nut, oil baffles and slingers, thread locker, gear marking compound with a brush, and silicone for the cover.
Drain the axle and check the oil and magnet; silver paste is normal, while flakes and rollers are not. Grab the pinion yoke and try to move it up and down; any radial play means pinion bearings. With the cover off, check backlash with a dial indicator and compare to the original marks. Wheel bearing noise on a full-floater can sound like a differential, so spin each raised wheel by hand and feel for roughness at the hub before tearing into the center section.
This kit fits the Dana Spicer 80 with a 4.125-inch outside-diameter pinion bearing. The Dana 80 was used in Dodge 3500 trucks from 1994 to 2002, Ford F-350 dually and F-450 trucks, and GM C3500 HD trucks from 1991 to 2002. Not every Dana 80 uses this bearing: later Ford axles use a larger 4.375-inch pinion bearing and need the separate 4.375-inch USA Standard kit. Measure the outer pinion race, or read the bearing numbers off the old cup, before you order. If you are not sure, send us your year, model and VIN or the axle tag and we will confirm. More axle kits are in our rebuild kits category.
A Dana 80 housing needs to be spread slightly to remove and install the carrier, so plan on a housing spreader and a dial indicator to keep from stretching it. Mark the bearing caps and record the old shim stacks and backlash at teardown; they are your starting point. Set pinion depth first, then build pinion bearing preload with the preload shims and torque the new pinion nut. Shim the carrier for backlash, paint the teeth with the marking compound and read the pattern on both drive and coast sides. Use the thread locker on the ring gear bolts. If new gears are going in, a set like the Yukon 3.73 Dana 80 gear set goes in with this kit; if the old cover leaked or is cracked, the Yukon Hardcore Dana 80 cover replaces it. Refill with heavy-duty gear oil in the grade your owner manual lists, plus friction modifier if the axle has a clutch-type limited slip.
| Brand | Yukon Gear & Axle |
| Part number | ZK D80-A |
| Fits | USA Standard Master Overhaul Kit For The Dana 80 Diff (4.125in OD Only) |
| Type | Differential Overhaul Kits |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Measure the outside diameter of the outer pinion bearing race, or read the part number stamped on the old bearing cup. If it is 4.125 inches this kit fits; if it is 4.375 inches, which later Ford axles use, you need the separate 4.375-inch kit.
The Dana 80 sets pinion bearing preload with shims rather than a crush sleeve, so the kit includes a complete shim kit instead.
No. The manufacturer contents list covers the center section only: carrier and pinion bearings and races, pinion seal, shims, ring gear bolts, pinion nut, baffles and slingers, thread locker, marking compound and silicone. Wheel bearings and hub seals on the full-floating axle are separate.
If the teeth are not pitted, chipped or scored, yes. Record the old shim stacks and backlash at teardown, set the gears back up with the new bearings, and check the contact pattern before closing the cover.
Plan on a housing spreader, a dial indicator, bearing pullers and a press. The carrier will not come out or go back in properly without spreading the housing slightly.
