USA Standard Master Overhaul Kit For The Chrysler 76-04 8.25in Diff

A rear end that howls at 45 mph in a Jeep Cherokee XJ, a Dakota or Durango with oil weeping from the pinion seal, or a Ram 1500 that rumbles on coast all point at the same job: new bearings and seals in the Chrysler 8.25 in. axle. The USA Standard ZK C8.25-B is the budget-minded master overhaul kit for that axle, covering 1976-2004 units. It is the Koyo-bearing counterpart to the Yukon-branded kit and it puts every bearing, race and seal for the center section in one box.

What is in the ZK C8.25-B kit

• Carrier bearings and races (Koyo, LM603049 / LM603012)
• Pinion bearings and races
• Pinion seal
• Complete shim kit
• Ring gear bolts and a new pinion nut
• Crush sleeve
• Thread locker
• Marking compound with brush
• Cover gasket

Axle shaft bearings and seals are not part of this kit, so price those separately if the wheel ends are leaking or noisy.

How the 8.25 center section works

The pinion rides in two tapered bearings and is held at preload by a crush sleeve that collapses as the nut is tightened, which is why a used sleeve should never go back in. Pinion depth is set with a shim under the inner pinion bearing. The carrier rides on two more tapered bearings, and on the 8.25 the carrier preload and the backlash are set with threaded side adjusters rather than stacked shims. Get either setting wrong and new bearings will whine almost as loudly as the worn ones.

Symptoms that call for this kit

• A whine that changes between acceleration and coast and climbs with road speed
• A growl or rumble that is still there in neutral at speed, pointing past the transmission
• Fore-and-aft play at the pinion yoke when you push and pull on it
• Gear oil slung on the yoke, driveshaft or crossmember
• A clunk taking up slack when you go from coast to throttle

How to confirm before you order

Drive to the speed where the noise appears, then shift to neutral and let the truck coast. If the noise stays, the axle or wheel bearings are the likely source; if it vanishes, look forward at the transmission, and our 46RE noise diagnosis guide helps on Ram and Durango trucks with that unit. Next, drain the axle and check the oil for chunks rather than fine paste, then pull the cover and inspect the ring and pinion. Pitted or chipped teeth mean gears too, such as a Chrysler 8.25 4.56 gear set, and this kit covers the bearings for that swap.

Fitment

The kit is listed for 1976-2004 Chrysler 8.25 in. rear axles. Published applications include 1991-2001 Jeep Cherokee, 1991-1992 Comanche, 2002-2004 Liberty, Dodge Dakota, Durango, Ramcharger, Ram 1500 and Ram vans, plus older Dodge, Chrysler and Plymouth passenger cars. Identify the 8.25 by its 10-bolt cover; the 9.25 uses 12 bolts. Chrysler moved to a revised 8.25 for 2005 and later, which takes a different kit. Axle shafts went from 27 to 29 splines in the mid-1990s, which affects lockers and axles but not these bearings. Not sure which axle you have? Send us the year and VIN. If you want Timken bearings, the Yukon YK C8.25-B kit fits the same axles, and more kits are in our rebuild kits section.

Install notes

• Mark the side adjusters and bearing caps before loosening anything, and paint the old gear pattern with the supplied compound so you have a reference.
• Press races in fully and check them with a feeler gauge; a race that is not seated reads as preload that disappears later.
• Tighten the pinion nut gradually and check turning torque often, because an over-crushed sleeve cannot be backed off.
• Use thread locker on the ring gear bolts and torque them in a cross pattern.
• Refill with 75W-90 gear oil, adding friction modifier only if the axle has a clutch-type limited slip.

Building an XJ? The front Dana 30 usually needs the same attention, and the Dana 30 front master overhaul kit pairs with this one.

What years does the ZK C8.25-B fit?

It is listed for 1976-2004 Chrysler 8.25 in. rear axles. The revised 2005-and-later 8.25 uses a different kit.

What is the difference between the ZK and YK versions?

Both cover the same axles with the same type of bearing and seal set. The ZK C8.25-B uses Koyo bearings and races; the Yukon YK C8.25-B uses Timken.

Does this kit include axle shaft bearings?

No. It covers the center section: carrier and pinion bearings and races, pinion seal, shims, crush sleeve, pinion nut, ring gear bolts, thread locker, marking compound and cover gasket.

Can I reuse my gears with this kit?

Yes, if the teeth are not pitted or chipped. Record the original pattern and backlash before teardown and set the new bearings to match.

How do I know I have an 8.25 and not a 9.25?

Count the cover bolts. The 8.25 has a 10-bolt cover and the 9.25 has 12. The axle tag on the cover bolt also lists the ratio.

• 46RE Noise Diagnosis (Whine/Clunk)