Ford F150 Pickup. Instruction - part 506

Fig. 6: Exploded View Of Rear Axle Legend - 10.25-Inch Ring Gear (2 Of 2) 
Courtesy of FORD MOTOR CO. 

Description 

The rear axle assembly has the following features:  

z

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

z

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.  

z

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

z

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

z

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

 

2003 Ford Pickup F150 

2003 DRIVELINE/AXLES Rear Drive Axle/Differential - Ford 10.25-inch - F150 Pickup

  

z

The differential pinion shaft (4211), which is retained by a differential pinion shaft lock bolt assembled to 
the differential case (4204).  

z

The differential case, which is mounted in the rear axle housing between two opposing differential 
bearings (4221) that are retained in the rear axle housing (4010) by removable bearing caps.  

z

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

z

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

z

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

z

The limited-slip differential containing a differential clutch packs (4947) 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 10.25-inch - F150 Pickup

  

Fig. 7: Identifying Differential Side Gear & Rear Axle Disc & Plate Kit Components 
Courtesy of FORD MOTOR CO. 

DIAGNOSIS & TESTING 

REAR DRIVE AXLE & DIFFERENTIAL 

Refer to DRIVELINE SYSTEMS - GENERAL INFORMATION .

 

2003 Ford Pickup F150 

2003 DRIVELINE/AXLES Rear Drive Axle/Differential - Ford 10.25-inch - F150 Pickup

  

The Traction-Lok(R) rear axle assembly, except for the differential case and its internal components is identical 
to the conventional rear axle (4001). The Traction-Lok(R) differential (4026) employs two multi-disc 
differential clutch packs 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 (1007) 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. 

GENERAL PROCEDURES 

DIFFERENTIAL BENCH TORQUE TEST 

Special Tool(s) 

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

rear axle 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 10.25-inch - F150 Pickup