USA Standard Master Overhaul Kit For The Dana 80 Diff (4.375in OD Only On 98 and Up Fords)

If the rear axle under your dually Ford Super Duty has started to howl at highway speed, growl when you pull a trailer, or weep oil from the pinion seal, the bearings and seal inside the Dana 80 are usually the cause, not the gears. The USA Standard ZK D80-B master overhaul kit is the budget-minded way to rebuild that axle: a new carrier and pinion bearing package with the seal, shims and hardware to put it back together. It is made for the Ford version of the Dana 80 that uses the larger 4.375 in. outside-diameter pinion bearing race, listed for 1999-2015 Super Duty trucks. USA Standard Gear is the value line from Yukon Gear & Axle.

What this kit replaces in a Dana 80

The Dana 80 is a full-floating rear axle: the hub bearings carry the truck and its load, the axle shafts only turn the wheels, and the carrier and pinion bearings exist to hold the ring and pinion in exact alignment under torque. On a one-ton dually that torque is constant, especially with a fifth-wheel or gooseneck hitched up. As the bearings wear, pinion preload drops, pinion depth wanders and backlash opens up, and the gear contact pattern moves off the center of the tooth. That is the howl you hear. Caught early, a bearing rebuild saves the gear set.

Per the manufacturer's listing, the ZK D80-B includes:

• Carrier bearings and races
• Pinion bearings and races
• Pinion seal and pinion nut
• Complete shim kit for setting pinion depth and carrier preload
• Ring gear bolts
• Oil baffles and slingers
• Thread locker, marking compound with brush, and silicone for sealing the cover

The bearings and races are Koyo. That is the main difference from the premium Yukon YK D80-B master kit, which covers the same axle with Timken bearings at a higher price.

Symptoms that point to a worn Dana 80

• Whine or howl that comes and goes with throttle at cruise
• A deeper growl under load or with a trailer, typical of a pitted pinion bearing
• Clunk on take-off or free play when you rock the pinion yoke
• Gear oil on the pinion seal, yoke or the inside of the rear tires
• Metallic paste on the drain plug or the inside of the cover

How to confirm before you buy

Support the axle, pull the driveshaft and turn the pinion by hand. Roughness, or any in-and-out movement at the yoke, means the pinion bearings or preload are gone. Drain the oil and look for glitter, then pull the cover and paint several ring gear teeth with marking compound to read the pattern. Clean teeth with a worn pattern call for this kit. Chipped, pitted or blued teeth mean gears too, and a set such as the Dana 80 3.55 ring and pinion should go in during the same teardown. Check the full-floating hub bearings as well; a dry hub can sound like a center-section problem.

Fitment

This kit fits the Dana 80 with the 4.375 in. OD pinion bearing race, listed for 1999-2015 Ford Super Duty applications. Not every Dana 80 is the same: axles with the smaller pinion race take the ZK D80-A kit for 4.125 in. OD. If you are not sure which you have, measure the old pinion head race once it is out, read the tag on the axle, or send us your year, model and VIN and we will confirm before it ships. Browse every axle and transmission kit in our rebuild kits collection.

Install notes

• Mark the carrier bearing caps before removal. They are line-bored with the housing and must go back in the same place and direction.
• The Dana 80 carrier is installed with preload, so use a case spreader like the Dana 30-80 housing spreader rather than prying it out.
• Start from the original pinion depth shim, then confirm depth and backlash with the marking compound and the supplied shims.
• Set pinion and carrier preload and torque the ring gear bolts with thread locker to the factory service manual figures.
• Seal the cover with the supplied silicone, fill with the gear oil your owner's manual lists, and add friction modifier only if a limited-slip carrier requires it. Re-check for leaks after the first drive.

Which trucks does the ZK D80-B fit?

It is listed for 1999-2015 Ford Super Duty trucks with the Dana 80 rear axle that uses the 4.375 in. OD pinion bearing race. Send us your VIN if you are unsure which race your axle has.

What is the difference between this kit and the Yukon YK D80-B?

Both cover the same Ford Dana 80. The USA Standard ZK D80-B uses Koyo bearings and races and costs less; the Yukon YK D80-B uses Timken bearings. Either one includes the seal, shims and hardware for a full rebuild.

Does the kit include a cover gasket?

It includes silicone for sealing the differential cover rather than a gasket, along with thread locker and marking compound with a brush.

Does it come with ring and pinion gears?

No. It is a bearing, seal, shim and hardware kit. If the gear teeth are chipped, pitted or discolored, order a Dana 80 ring and pinion to install at the same time.

Can I do the rebuild at home?

Only with the right tools: a bearing puller and press, a case spreader, a dial indicator for backlash and an inch-pound torque wrench for preload. Without them, have a driveline shop set up the axle.