Ford F150 Pickup. Manual

identical to the conventional rear axle (4001). The Traction-Lok(R) differential (4026) employs two multi-disc
differential clutch packs (4947) to control differential action. The mounting distance of the differential side gear
(4236) is controlled by eight plates on each side: four steel and four friction. Also included is one steel selective
shim to control the position of the differential side gear (shim selection may determine that two select shims be
used), and one Belleville spring plate which, because of its slight concave design, provides initial preload to the
differential clutch pack. Additional clutch pack capacity is delivered from the thrust loads of the differential
side gear. Steel clutch plates are splined to the side gear hub which, in turn, is splined into the axle shaft (4234).
Tabs on the friction plates are captured in the case by matching slots, thus providing continuous engagement of
the differential clutch packs.

Operation

The pressure between differential clutch packs opposes differential action at all times. When the vehicle turns a
corner, the differential clutch pack slips, allowing normal differential action to take place. Under adverse
weather conditions, in which one or both wheels are on a low traction surface, such as snow, ice or mud, the
friction between the clutch plates will transfer a portion of the usable torque to the wheel with the most traction.
Thus, the wheel that is on ice or snow will have a tendency to operate with the opposite wheel in a combined
driving effort.

The rear axle assembly has the following features:

An integral-type housing hypoid gear design (center of the pinion set below the centerline of the
differential ring gear).

The hypoid differential ring gear and pinion consisting of a ring gear and an overhung drive pinion that is
supported by two opposed tapered roller bearings.

Pinion bearing preload, which is maintained by a drive pinion collapsible spacer (4662) on the drive
pinion shaft and adjusted by the pinion nut.

The axle housing assembly consisting of a cast center section with two steel tube assemblies and a
stamped differential housing cover (4033).

The differential housing cover, which uses silicone sealant as a gasket.

The differential pinion shaft (4211), which is retained by a differential pinion shaft lock bolt assembled to
the differential case.

DIAGNOSIS & TESTING

REAR DRIVE AXLE & DIFFERENTIAL

Refer to DRIVELINE SYSTEMS - GENERAL INFORMATION .

The differential case, which is mounted in the rear axle housing (4010) between two opposing differential

CAUTION: Extended use of other than matching size spare tires on a Traction-Lok(R)

rear axle (4001) could result in a permanent reduction of the axle's ability
to provide added traction on slippery surfaces. This loss of effectiveness
does not affect normal driving and should not be noticeable to the driver.

2003 Ford Pickup F150

2003 DRIVELINE/AXLES Rear Drive Axle/Differential - Ford 9.75-inch - F150 Pickup

bearings (4221) that are retained in the carrier by removable bearing caps.

Uses SAE 75W-140 High Performance Rear Axle Lubricant F1TZ-19580-B or equivalent meeting Ford
specification WSL-M2C192-A.

Differential bearing preload and differential ring gear backlash adjusted by differential bearing shims
located between the differential bearing cups (4222) and the rear axle housing.

Rear axle identification on an embossed metal tag bolted to the differential housing cover.

The limited-slip differential containing a differential clutch pack arranged as shown in the illustration.

Differential Side Gear & Rear Axle Disc & Plate Kit

2003 Ford Pickup F150

2003 DRIVELINE/AXLES Rear Drive Axle/Differential - Ford 9.75-inch - F150 Pickup

Ford F150 Pickup. Manual - part 596