Yukon Gear Master Overhaul Kit For 11+ Ford 9.75in Diff

A 2011-or-newer F-150 with the 9.75 in. rear that has started to whine on the highway, especially while towing, or that clunks when you take off and leaks at the pinion, needs its bearings replaced before the gears go with them. The Yukon Gear & Axle YK F9.75-D master overhaul kit is built for the redesigned 2011-up Ford 9.75 found under max-tow and heavy-payload F-150s, plus some E-150 and Transit vans. It contains the bearings, races, seal, shims and hardware for a complete center-section rebuild.

What the overhaul kit does in a 2011-up Ford 9.75

The 9.75 is a semi-floating axle with C-clip shafts, a 12-bolt cover and a 9.75 in. ring gear. The pinion rides on two tapered roller bearings with preload set by a crush sleeve, and pinion depth is set with a shim. The carrier rides on two more tapered bearings positioned by shims that set backlash and side load. For the 2011 model year Ford redesigned this axle: pinion and carrier bearings, shims and internal dimensions changed, which is why the 2010-and-older kit will not fit. Yukon's own setup chart even lists different pinion preload for the two generations.

Inside the YK F9.75-D kit you get Timken carrier bearings and races, pinion bearings and races, a pinion seal, a complete shim kit, a pinion nut, a crush sleeve, thread locker, marking compound with a brush and a cover gasket.

Symptoms that call for a 9.75 overhaul

• A whine somewhere around 45-70 mph that rises on throttle and drops off on coast: pinion bearings and the drive side of the gears.
• A constant rumble that does not change with throttle: carrier bearings.
• In-and-out play at the pinion flange, or a clunk on take-off. The crush sleeve has lost preload. Tightening the nut will not fix it.
• Gear oil around the pinion seal, or a low level after a long tow.
• Fine metal on the cover or drain plug magnet.

How to confirm before you buy

Drive at the speed where the noise peaks and check it on throttle, cruise and coast. Diff noise changes with load; wheel bearing noise changes when you swerve. Check pinion play by hand, then pull the cover and look at the oil and gear pattern. Gear oil on the inside of a rear wheel is a different problem: on 2011-up 9.75 trucks that usually means axle seals pushed out by a plugged vent or an overfilled housing, not worn diff bearings. Our Ford 9.75 rear axle problems guide covers both, and the whine diagnosis guide helps pin down the noise.

Fitment

Distributor fitment for YK F9.75-D lists 2011-2017 F-150, 2011-2015 E-150 and 2015-2017 Transit 150, 250 and 350 with the 9.75 in. rear, and other catalogs extend the F-150 range to 2023. Some catalogs also flag the pinion nut thread pitch, so compare the new nut with the one on your truck. If your truck is 2010 or older, use the Ford 9.75 master overhaul kit for 2000-2010 instead. Count the cover bolts (12 on a 9.75, 10 on an 8.8; see 8.8 vs 9.75 differences) and read the axle code on the door sticker, or send us the year and VIN. Browse more kits in our rebuild kits collection.

Install notes

• Yukon's chart for the 2011-up 9.75 calls for 17-25 in-lb of pinion bearing preload with new bearings (8-12 in-lb if reusing used ones), 0.006-0.011 in. backlash for 5-cut gears and 0.008-0.012 in. for 2-cut, 95 ft-lb on the ring gear bolts and 70 ft-lb on the bearing caps.
• Pull the C-clips and shafts first, then the carrier. Keep the old shims labeled by side as a starting point.
• Crush the sleeve slowly and check rotating torque with an inch-pound wrench. Overshoot means a new sleeve.
• Planning a ratio change? The Yukon 3.73 gear set for 2011-up 9.75 pairs with this kit. A limited-slip or spider gear rebuild can be done at the same time with the Yukon Dura Grip for 34-spline 9.75.
• Fill to the level Ford specifies for your truck, not to the top of the fill hole, and add friction modifier if the axle has a clutch-type limited slip.

Will this kit fit my 2010 F-150 with a 9.75?

No. Ford redesigned the 9.75 for 2011, changing the bearings and shims. A 2010-and-older axle takes the early-design 9.75 kit, such as our Ford 9.75 master overhaul kit for 2000-2010.

How do I know my F-150 has the 9.75 and not the 8.8?

Count the cover bolts: the 9.75 has 12, the 8.8 has 10. You can also read the axle code on the door sticker or send us your VIN.

Does this fix oil leaking onto my rear brakes?

Not by itself. That leak is at the axle seals, often caused by a plugged vent or overfilling. This kit includes the pinion seal, not axle shaft seals.

What pinion preload do I set with new bearings?

Yukon lists 17-25 in-lb of rotating torque for new bearings on the 2011-up 9.75, which is higher than the 15-19 in-lb listed for the 2010-and-older design.

Can I keep my original ring and pinion?

Yes, if the teeth are not pitted, chipped or scored. Record the old backlash and pattern, then set the new bearings to match.