Yukon Gear Dana 44 and Chrysler 9.25in Tracloc Clutch Kit Replacement

When a Trac-Lok rear in a Jeep or a Chrysler 9.25 truck axle starts acting like an open differential, so one tire spins in mud, snow or a wet launch while the other sits still, the clutch packs inside the carrier are worn out. Yukon Gear and Axle YPKD44-PC-T/L is the replacement clutch kit for the standard Dana 44 Trac-Lok and the Chrysler 9.25 in Trac-Lok. It lets you rebuild the limited slip you already have instead of buying a new carrier or converting to a locker.

What the clutch packs do in a Trac-Lok

A Trac-Lok is a clutch-type limited slip. Behind each side gear sits a stack of friction discs splined to the side gear and steel plates tabbed to the carrier case, held under preload by a spring. When both tires have grip, the packs slip so the outside wheel can turn faster in a corner. When one tire loses grip, the separating force from the spider gears clamps the packs harder and sends torque back to the tire that still has traction. The friction surfaces wear every time the axle turns a corner, so after enough miles the preload and clamp are gone and the axle behaves like an open differential.

Symptoms of worn Trac-Lok clutches

• One wheel spins freely in snow, mud or on a launch while the other does not move
• Lifting one rear tire, the opposite tire no longer resists when you turn the raised one
• Chatter, groan or a stick-slip shudder in tight, slow turns that a friction modifier refill no longer cures
• Clunk or bang from the rear when coming off a turn
• Dark, glittery gear oil with fiber debris at the drain plug or on the magnet

How to confirm before you tear it down

Start with the cheap fix. A Trac-Lok that chatters is often just starved of friction modifier or running the wrong oil. Drain, refill with the correct gear oil plus limited slip additive, and drive a few figure-eights. Our Trac-Lok chatter fix guide covers that order of operations, and the friction modifier dosing guide explains why too much additive makes the axle act open. If the axle still spins one wheel after a correct service, or it never had much bite, the packs are worn and this kit is the repair. A fluid transfer pump makes the refill easy.

Fitment

This kit is listed for the standard Dana 44 Trac-Lok and the Chrysler 9.25 in Trac-Lok. Those are separate axles, so confirm which one you have from the axle tag and cover shape. The Dana 44 HD rear used under 1996-2004 ZJ and WJ Grand Cherokees takes a different Yukon set, YPKD44HD-PC-T/L, not this one. Ford 8.8 Traction-Lok axles are not covered either; they take the Ford 8.8 Traction-Lok clutch kit. Clutch pack sizes can vary with spline count and carrier design, so lay the new plates next to your old ones before assembly, or send us your year, VIN and axle tag and we will check it. More axle parts are listed under rebuild kits.

Install notes

• Pull the axle shafts, remove the carrier and take the pinion shaft out, then rotate the spider gears out to free the side gears and clutch packs.
• Keep each old pack in order and measure its total stack height; the new pack needs to give the same preload once installed.
• Soak the new friction discs in limited slip friction modifier or the gear oil you will run, and build each stack in the same order as the old one.
• Check the side gears, spider gears and thrust washers while it is apart. Worn thrust surfaces are worth replacing with the Chrysler 9.25 side gear and thrust washer kit.
• If the carrier bearings are rough or the cups are pitted, install new ones before the carrier goes back in. The Dana 44 carrier installation kit or the Chrysler 9.25 master overhaul kit covers the bearings, shims and seals.
• Refill with 75W-90 or 75W-140 gear oil plus friction modifier unless the oil already contains it, and drive gently with a few slow figure-eights to bed in the plates.

For the bigger picture on these axles, see Dana 44 problems and rebuild cost and Chrysler 9.25 problems and rebuild cost.

How do I know my axle has a Trac-Lok and not an open differential?

Raise both rear tires with the transmission in neutral and turn one tire by hand. With a working Trac-Lok, the other tire turns the same direction. With an open differential it turns the opposite way. The axle tag and a limited slip note on the cover also help.

Will this fit my Grand Cherokee ZJ or WJ Dana 44?

The 1996-2004 ZJ and WJ rear Dana 44 is the HD design, which takes the YPKD44HD-PC-T/L set. This kit is for the standard Dana 44 Trac-Lok and the Chrysler 9.25 Trac-Lok.

Do I need friction modifier after installing new clutches?

Yes, unless your gear oil already contains limited slip additive. Soak the new discs before assembly, then fill with gear oil plus the right dose of modifier. Too little causes chatter in turns, and too much lets the packs slip.

Can I just add friction modifier instead of rebuilding?

If the only complaint is chatter in tight turns, try a fluid change with the correct additive first. If one tire still spins freely after that, the packs are worn and additive will not bring the bite back.

Should I replace the carrier bearings at the same time?

If the carrier is out and the bearings are rough, noisy or original on a high-mileage axle, it is cheap insurance to replace them and reset backlash while everything is apart.