Yukon Gear 2019+ RAM 2500/3500 Master Overhaul Kit 9.25in

A 2019 or newer Ram 2500 or 3500 that hums from the front end with four-wheel drive engaged, whines on the highway even in 2WD, or shows gear oil around the front pinion is pointing at the AAM 9.25 inch front differential. The Yukon Gear and Axle YK C9.25-F-B is the master overhaul kit Yukon builds for that later front axle. It carries the bearings, races, shims, seal and hardware for a complete rebuild or a regear, matched to the 2019-up design instead of the 2003-2018 kits.

What the master overhaul kit does in the 2019+ AAM 9.25 front

The current-generation Ram heavy duty trucks pair a 9.25 inch AAM front axle with an 11.5 or 12.0 inch AAM rear. In the front unit, the pinion turns on two tapered bearings held in preload by a crush sleeve, and the carrier rides on two side bearings with shims that set backlash. Pinion depth is set by its own shim. A diesel Ram puts a lot of weight and torque on that front pinion, and once bearing preload is lost the gear contact moves toward the edge of the teeth. That is where the noise starts.

Yukon lists the YK C9.25-F-B contents as carrier bearings and races, pinion bearings and races, a pinion seal, a complete shim kit, ring gear bolts, a pinion nut, a crush sleeve, thread locker, marking compound with a brush, and a gasket. Bearings and races are Timken or Koyo. Inner axle seals are not listed in this kit, so check yours and order them separately if they are leaking.

Symptoms of a worn front differential

• A whine or howl from the front that gets louder in 4WD or changes with throttle
• Noise that remains in 2WD, because the front ring and pinion still turn with the wheels
• Clunk when engaging 4WD or when loading and unloading the front driveshaft
• Play at the front pinion yoke, or oil on the yoke and front driveshaft
• Gear oil running down the axle tubes toward the knuckles, often from inner axle seals
• Glitter or bearing flakes on the fill plug or in drained oil

How to confirm before ordering

Check whether the noise changes between 2WD and 4WD, and between drive and coast. Our Chrysler 9.25 axle problems and rebuild cost guide explains how the AAM front differs from the Chrysler and ZF rears and where it leaks, and whine on acceleration vs deceleration helps narrow down which bearing is worn. Then check the yoke for play, drain the oil, and take a backlash reading with a dial indicator and magnetic base before you take anything apart.

Fitment

This kit is listed for the 9.25 inch front differential in 2019 and newer Ram 2500 and Ram 3500 four-wheel-drive trucks. Earlier 2003-2018 heavy duty trucks use the C9.25-F style kit, such as the USA Standard ZK C9.25-F, and the bearings and shims are not the same. If your truck was built near a model-year change or the axle has been swapped, compare the bearing numbers on the old parts or send us your VIN and we will confirm before it ships.

Install notes

• Yukon's setup chart for the 9.25 AAM front lists pinion bearing preload at 15-25 in-lb with new bearings, 0.006-0.011 in backlash on 5-cut gears, 90 ft-lb on the ring gear bolts and 63 ft-lb on the bearing caps. Measure preload with an inch-pound torque wrench.
• Use the new crush sleeve and tighten the pinion nut a little at a time; an over-crushed sleeve has to be replaced.
• Keep each bearing cap on its original side and in the same direction.
• If the inner axle seals are leaking, replace them while the carrier is out using an AAM 9.25 inner axle seal installer so they go in square.
• Front carrier bearings are pressed on tight; a bearing separator and puller set removes them without damaging the carrier journals.
• Install the cover with the included gasket and refill with the gear oil grade in your owner manual.

Will this kit fit my 2017 Ram 2500?

No. The YK C9.25-F-B is for the 2019 and newer front axle. 2003-2018 Ram 2500 and 3500 trucks use the earlier C9.25-F kits, which have different bearings and shims.

Does the kit include inner axle seals?

No. Yukon lists carrier and pinion bearings and races, pinion seal, shim kit, ring gear bolts, pinion nut, crush sleeve, thread locker, marking compound and a gasket. Order inner axle seals separately if yours leak.

Can I use this kit to regear my front axle?

Yes. It has everything needed to set up a new ring and pinion: bearings, races, a complete shim kit, crush sleeve, pinion nut and ring gear bolts. The front and rear ratios must match.

What preload and backlash should I set?

Yukon's 9.25 AAM front specs are 15-25 in-lb pinion bearing preload with new bearings and 0.006-0.011 in backlash on 5-cut gears, with 90 ft-lb ring gear bolts and 63 ft-lb bearing caps.

Why does my front diff whine even in 2WD?

On these trucks the front ring and pinion still turn with the wheels when 4WD is off, so a worn front pinion bearing can make noise in 2WD too. Check for yoke play and inspect the oil.