Yukon Gear Master Overhaul Kit For Dana 50 Diff / Straight Axle

Front axle whine in 4WD, a growl that follows road speed, or gear oil seeping from the pinion on a 1999-2002 F-250 or F-350 Super Duty or a 2000-2005 Excursion usually means the Dana 50 center section needs bearings. The Yukon Gear & Axle YK D50-STRAIGHT master overhaul kit is made for the straight-axle Dana 50 front, not the earlier Twin Traction Beam version, and it carries every bearing, seal and setup part needed to rebuild the carrier and pinion in one job.

What the overhaul kit does in a Dana 50 straight axle

On the Super Duty and Excursion, the Dana 50 is a solid front housing with the ring and pinion in the center and 30-spline shafts out to the knuckles. Like other Dana axles, the carrier is located by shims behind the carrier bearings and is preloaded by the housing itself, which is why a spreader is normally used to remove and install it. Shims under the inner pinion bearing set pinion depth. When those bearings wear, the shim stack no longer holds the gears where they were set, and the pattern and noise go downhill together.

The kit includes Timken carrier bearings and races, pinion bearings and races, the pinion seal and axle seals, a complete shim kit, ring gear bolts, a pinion nut, a crush sleeve, oil baffles and slingers, thread locker, marking compound with a brush, and silicone.

Symptoms of a worn Dana 50 front differential

• A howl that appears or gets louder with the hubs locked and 4WD engaged.
• Growl or rumble at speed that is there in 2WD too, often from a carrier bearing.
• Pinion seal leak and low oil, which starves the pinion head bearing first.
• Play at the yoke or a clunk when shifting into 4WD.
• Metal on the fill plug or in the oil after deep water crossings or plow use.

How to confirm before you buy

Separate front diff noise from hub and u-joint noise first. A failing unit-bearing hub changes pitch as you steer side to side, and a bad axle u-joint clicks or binds in turns. Diff noise follows speed and load. Drive in 2WD and 4HI on the same road, then pull the cover and inspect the oil, the pattern and pinion play. Our Dana 50 front axle problems page covers the hub, ball joint and u-joint issues that get mistaken for diff noise, and our carrier bearing noise guide helps pin down the bearing.

Fitment

Listed applications are the Dana 50 straight front axle in 1999-2002 F-250 and F-350 Super Duty, 2000-2005 Excursion, and 1998-1999 F-250. Ford put a Dana 50 under some Super Duty trucks and a Dana 60 under others, and the two look alike, so read the axle tag or the door sticker code before ordering; the Dana 60 ring gear is the larger of the two. The 1980-1998 TTB Dana 50 uses a different kit. If in doubt, send your year and VIN. For other kits see our rebuild kits collection.

Install notes

• Yukon's Dana 50 setup row lists 14-19 in-lb pinion preload with new bearings (6-9 in-lb used), 0.006-0.011 in. backlash on 5-cut gears and 60 ft-lb on the bearing caps. Ring gear bolt torque depends on bolt size: 75 ft-lb for 7/16 in. or 135 ft-lb for 1/2 in.
• Spread the housing only as far as needed to lift the carrier out. A Dana 30-80 housing spreader keeps you from prying on the cover face; our spreader guide explains the limits.
• Crush the new sleeve in small steps and check rotating torque with an inch-pound torque wrench. Overshoot means a new sleeve.
• Inspect the spider gears and cross shaft while the carrier is out. Worn ones can be replaced with the Yukon Dana 50 30-spline spider gear kit.
• Reinstall the hubs with new spindle nuts, such as the Yukon Dana 50/60 spindle nut kit, and refill with the gear oil and capacity in your owner guide.

Does this fit the Dana 50 TTB front on my 1990s F-250?

No. This kit is for the straight-axle Dana 50 on Super Duty trucks and the Excursion. The Twin Traction Beam Dana 50 uses a different overhaul kit.

How do I know if my Super Duty has a Dana 50 or a Dana 60?

Check the axle tag on a cover bolt or the axle code on the door sticker. Without a tag, the Dana 60 ring gear is noticeably larger. Send us the VIN if you are unsure.

Do I need a housing spreader?

Dana carriers are preloaded by the housing and shims, so a spreader is the right way to remove and install the carrier without damaging bearings or the housing.

Are hub bearings or u-joints included?

No. The kit covers the differential: carrier and pinion bearings and races, pinion and axle seals, shims, ring gear bolts, pinion nut, crush sleeve, baffles and slingers. Hubs and u-joints are separate.

Can I keep my original gears?

Yes, if the teeth are not damaged. Measure and record the original shim stacks and backlash before teardown so you can return the gears to the same position.