USA Standard Master Overhaul Kit For The Ford 9in Lm603011 Diff
If your Ford 9-inch howls at highway speed, rumbles more the faster you go, or has been dripping gear oil off the pinion yoke, the bearings and seal in the third member are usually the reason. The USA Standard Gear ZK F9-C master overhaul kit is built for 9-inch center sections that run the larger LM603011 carrier bearing race, the size you find in many heavy-duty and aftermarket nodular iron cases used in street, strip and trail builds. It is a new kit with Koyo bearings and races and the small parts needed to set the gears up from scratch.
Ford built the 9-inch from the 1957 model year through 1986, and aftermarket companies still make new housings and cases for it. It is a drop-out axle: the ring gear, pinion, carrier and pinion support live in one removable third member that you rebuild on the bench. The pinion is straddle-mounted, so it is supported on both sides of the gear head, and the two carrier bearings are loaded by threaded adjusters instead of a shim stack. Every one of those bearings is a wear item. Once a race pits or a roller cage loosens, the pinion and carrier move under torque, the tooth contact drifts and the noise starts.
The listed contents of the ZK F9-C are:
The published contents do not mention a pinion pilot bearing, so inspect the one in your case. If it is rough or loose, replace it at the same time rather than reusing a tired part.
Start with the axle bearings, because a dry or pitted wheel bearing makes a hum that changes in turns and is easy to mistake for a pinion problem. If the noise changes with cornering load, the 9-inch tapered axle bearing and seal kit may be the real fix. Next, with the rear raised and the transmission in neutral, turn the yoke by hand and push it in and out; roughness or end play points to the pinion bearings. Pull the third member and look at the ring gear teeth before ordering. Chipped or scored teeth mean the gears need replacing, and a set like the Revolution Gear 9-inch 3.50 ring and pinion goes in with this kit.
This kit fits Ford 9-inch third members that use the LM603011 carrier bearing race. Spline count and housing year do not tell you which carrier bearing is in your case, so read the part number on the old cup or measure the bore before ordering. Cases that use the smaller races need a different kit: the ZK F9-B for LM501310 races or the LM102910 kit with a crush sleeve eliminator. Not sure which one you have? Send us the bearing numbers or a photo of the case and we will confirm. More options are in our rebuild kits section.
Set pinion depth first. Pinion depth on a 9-inch is changed with shims between the pinion support and the case; if the supplied spread does not land you where you need to be, add a 9-inch pinion depth shim kit. Tighten the pinion nut in small steps while checking rotating torque so you do not over-crush the sleeve; if you overshoot, install a new sleeve rather than backing the nut off. Then set backlash and carrier preload with the threaded adjusters, lock them, and confirm the pattern on both drive and coast sides using the marking compound. A dial indicator with a magnetic base makes backlash readings repeatable. Use Loctite on the ring gear bolts, torque them evenly, and refill with 75W-90 or 85W-140 gear oil as your build calls for, adding friction modifier only if the carrier is a clutch-type limited slip. Drive gently for the first few hundred miles so the new gears can break in.
| Brand | Yukon Gear & Axle |
| Part number | ZK F9-C |
| Fits | USA Standard Master Overhaul Kit For The Ford 9in Lm603011 Diff |
| Type | Differential Overhaul Kits |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Read the number stamped on the old carrier bearing cup or measure the carrier bore in the case. LM603011 is the larger of the common 9-inch carrier races. Spline count and the year of the housing are not reliable ways to tell, so check the bearing itself or send us a photo.
The listed contents for the ZK F9-C do not include a pilot bearing. Inspect the one in your third member and replace it separately if it feels rough or has any play.
Yes, if the teeth are not chipped, pitted or scored. You will still need to reset pinion depth, preload and backlash, because new bearings change the stack heights. If the gears are damaged or you are changing ratio, replace them now while the third member is apart.
Most 9-inch builds run 75W-90 or 85W-140 gear oil. If the carrier is a clutch-type limited slip, add friction modifier unless the oil already contains it.
If they are noisy or the axle seals leak, yes. Axle bearing noise changes in turns, while pinion and carrier bearing noise changes with throttle and coast. The axles must come out for some housing work anyway, so it is a good time to do both.
