Yukon Gear 99+ F450 & F550 Axle Bearing & Seal Kit

An F-450 or F-550 that growls from one rear corner when it is loaded, throws gear oil across the inside of the inner dual, or has rear brakes that suddenly grab on one side is telling you a rear hub bearing or wheel seal is done. The Yukon Gear & Axle AK F450 is the axle bearing and seal kit for the heavy Dana rear axles under 1999-and-later Ford F-450 and F-550 Super Duty trucks. Yukon lists it as an axle bearing and seal kit that services one side of the axle, so a full rear job on both hubs takes two kits.

What the axle bearing and seal kit does on an F-450 or F-550 rear axle

The Dana 80, S110 and S135 rears under these trucks are full-floating axles. Each hub rides on tapered roller bearings on a spindle that is part of the axle housing, and that spindle carries the weight of the truck, the body and whatever is on the bed or the hitch. The axle shaft only slides through the middle and bolts to the hub face to turn it. Gear oil from the center section flows out the tubes to lubricate the hub bearings, and the seal at the back of the hub is what keeps that oil out of the brakes. On a work truck that spends its life near its rated weight, the bearings wear and the seal hardens long before anything inside the differential gives up. Our full-floating vs semi-floating axle guide explains why a broken shaft on these axles does not drop the wheel, but a failed hub bearing can.

Symptoms of a worn rear hub bearing or leaking wheel seal

• A hum or growl from one rear corner that climbs with road speed and gets worse with a load on
• Noise that changes as the truck leans through a long curve and shifts weight off one hub
• Gear oil streaked on the inner dual wheel, the backing plate or the brake parts
• A rear brake that pulls, grabs or fades after oil reaches the linings
• Low gear oil in the center section with no leak at the pinion or the cover
• Wheel play you can feel by rocking a raised rear tire top to bottom, or one hub much hotter than the other after a run

How to confirm it before you order

Chock the front, raise the rear until the duals clear the ground and set the axle on stands. Rock each wheel at twelve and six o'clock and spin it by hand, comparing the two sides for play and roughness. Pull the axle shaft on the suspect side; a wet hub cavity, dark gritty oil or a pitted race confirms it. If both hubs are tight and quiet and the noise follows throttle on and off, the sound is more likely in the pinion or carrier bearings, and the center section needs a Yukon Dana 80 master overhaul kit for 1998-up Fords instead. Our Dana 80 rear axle problems guide covers how to tell hub noise from gear and bearing noise.

Fitment

Yukon's dealer fitment for the AK F450 lists the 1999-2012 Ford F-450 Super Duty and F-550 Super Duty with one of these rear axles:

• Dana 80 rear, 35 or 37 spline, 1998-and-newer Ford version
• Dana S110 rear
• Dana S135 rear

This is not the kit for a Super Duty F-250 or F-350 pickup with the Sterling 10.5 rear, and the 2017-and-later F-450 and F-550 moved to the Dana M300 rear, which Yukon services with different parts. Many F-450 and F-550 trucks are chassis cabs with upfitted bodies, so the axle tag or the build sheet is the fastest way to be sure. Read the tag on the housing or send us your year, model and VIN and we will confirm the axle before it ships. Order one kit per hub. Other parts for this axle family, including a 37-spline Dana 80 replacement axle shaft, are in our hard parts listings.

Install notes

• Park on level ground and have a drain pan under the hub; gear oil follows the shaft out when it is pulled.
• Remove the shaft, the hub lock and the adjusting nut, then slide the hub and wheels off together with a wheel dolly. A dual hub and wheel assembly is heavy.
• Drive the old races out and seat the new ones fully against their shoulders, then pre-lube the bearings with the same gear oil the axle runs.
• Drive the new seal in square to its bore. A cocked seal will leak on the first loaded trip.
• Set the bearing adjustment exactly to the Ford service procedure for your model year, then install the lock and a new shaft flange gasket.
• Clean all oil off the brakes and replace any linings it soaked. If the center section is also tired, a Dana 80 carrier bearing kit and a Yukon Hardcore Dana 80 cover are worth doing while it is apart.
• Refill to the bottom of the fill hole with the gear oil grade and capacity in your owner's manual, then recheck the level after the hub oil has run back.

Does one AK F450 kit do both rear hubs?

No. Yukon lists this kit as servicing one side. To do both rear hubs on an F-450 or F-550, order two kits.

Will it fit my 2006 F-350 dually?

Most Super Duty F-350 pickups use the Sterling 10.5 rear, which this kit is not listed for. The AK F450 is listed for F-450 and F-550 Super Duty trucks with the Dana 80, S110 or S135 rear. Read your axle tag or send us your VIN and we will check.

Does it fit a 2018 F-550?

The dealer fitment for this kit runs 1999-2012. The 2017-and-newer F-450 and F-550 use the Dana M300 rear, which takes different parts. For 2013-2016 trucks, send us the VIN so we can confirm the axle before you order.

How do I know it is a hub bearing and not the differential?

Hub bearing noise follows road speed and changes when the truck leans in a curve. Differential bearing or gear noise usually changes when you go on and off the throttle. Raise the axle and check each hub for play and roughness to be sure.

What gear oil goes back in after the job?

Use the grade and capacity in your owner's manual for your axle. Hub bearings on these axles are lubricated by the same gear oil, so top up after the oil has had time to run out to the hubs and recheck the level.

Do I need to replace the brakes too?

If the old seal leaked gear oil onto the shoes or pads, yes. Oil-soaked linings will not recover. Clean the drums or rotors and replace the contaminated linings.