Ford F150 Pickup. Instruction — part 642

Axle Shaft Seals

Axle shaft oil seals are susceptible to the same kinds of damage as axle drive pinion seals if incorrectly
installed. The seal bore must be clean and the lip handled carefully to avoid cutting or tearing it. The axle shaft
journal surface must be free of nicks, gouges, and rough surface texture.

Differential Seals

For additional information on differential seals, refer to REAR DRIVE AXLE/DIFFERENTIAL-FORD 8.8-
INCH or REAR DRIVE AXLE/DIFFERENTIAL-FORD 9.75-INCH for the rear axle or FRONT DRIVE
AXLE/DIFFERENTIAL-FORD 8.8-INCH for the front axle.

Analysis of Vibration

Few vibration conditions are caused by the front or rear axle. On a vibration concern, follow the diagnosis
procedure in Section NOISE, VIBRATION & HARSHNESS unless there is a good reason to suspect the axle.

Tires

Most vibration in the rear end is caused by tires or driveline angle.

Vibration is a concern with modern, high-mileage tires if they are not "true" both radially and laterally. They are
more susceptible to vibration around the limits of radial and lateral runout of the tire and wheel assembly. They
also require more accurate balancing. Wheel and tire runout checks, truing and balancing are normally done
before axle inspection. Refer to WHEELS & TIRES - F150 PICKUP .

Driveline Angle

Driveline angularity is the angular relationship between the engine crankshaft (6303), the driveshaft, and the
rear axle pinion. Factors determining driveline angularity include ride height, rear spring and engine mounts.

Driveline Angle

WARNING:

A vehicle equipped with a Traction-Lokohm differential will always have
both wheels driving. If only one wheel is raised off the floor and the rear
axle is driven by the engine, the wheel on the floor could drive the vehicle
off the stand or jack. Be sure both rear wheels are off the floor.

WARNING:

Do not balance the wheels and tires while they are mounted on the
vehicle. Possible tire disintegration/differential failure can result, causing
personal injury/extensive component damage. Use an off-vehicle wheel
and tire balancer only.

2003 Ford Pickup F150

2003 GENERAL INFORMATION Driveline System - General Information - F150 Pickup

Fig. 12: Identifying Driveline Angle
Courtesy of FORD MOTOR CO.

An incorrect driveline (pinion) angle can often be detected by the driving condition in which the vibration
occurs.

z

A vibration during coasting from 72 to 56 km/h (45 to 35 mph) is often caused by a high axle pinion
angle.

z

A vibration during acceleration, from 56 to 72 km/h (35 to 45 mph) may indicate a low pinion angle.

When these conditions exist, check the driveline angles as described in the General Procedures portion of this
section.

If the tires and driveline angle are not the cause, carry out the NVH tests to determine whether the concern is
caused by a condition in the axle. Refer to NOISE, VIBRATION & HARSHNESS - F150 PICKUP .

Universal Joint (U-Joint) Wear

Place the vehicle on a frame hoist and rotate the driveshaft by hand. Check for rough operation or seized U-
joints. Install a new U-joint if it shows signs of seizure, excessive wear, or incorrect seating. Refer to
DRIVESHAFT & UNIVERSAL JOINTS - F150 PICKUP .

Wheel Hub or Axle Flange Bolt Circle Runout

2003 Ford Pickup F150

2003 GENERAL INFORMATION Driveline System - General Information - F150 Pickup

1. Position the special tool perpendicular to the wheel hub or axle flange bolt, as close to the hub or flange

face as possible. Zero the indicator to allow the pointer to deflect either way.

Fig. 13: Positioning Special Tool Perpendicular To Wheel Hub
Courtesy of FORD MOTOR CO.

2. Rotate the hub or flange until the next bolt is contacted. Record the measurement and continue until each

bolt is checked. The difference between the maximum and minimum contact readings will be the total
wheel hub or axle flange bolt pattern runout. The runout must not exceed 0.38 mm (0.015 inch).

Pilot Runout

1. Position the special tools to the pilot as close to the hub or axle flange face as possible. Zero the indicator

to allow the pointer to deflect either way.

NOTE:

The brake discs/drums must be removed to carry out all runout measurements.

2003 Ford Pickup F150

2003 GENERAL INFORMATION Driveline System - General Information - F150 Pickup

Fig. 14: Positioning Special Tools To Pilot As Close To Hub Or Axle Flange Face As Possible
Courtesy of FORD MOTOR CO.

2. Rotate the hub or flange one full turn and note the maximum and minimum readings. The difference

between the maximum and minimum readings will be the total pilot runout. Pilot runout must not exceed
0.15 mm (0.006 inch).

Wheel Hub or Axle Flange Face Runout

1. Position the special tool on the wheel hub or axle flange face, as close to the outer edge as possible. Zero

the indicator to allow the pointer to deflect either way.

NOTE:

If the axle shaft assembly is removed, check runout of the shaft itself. The
forged (unmachined) part of the shaft is allowed to have as much as 3.0 mm
(0.120 inch) runout. This alone will not cause a vibration condition.

2003 Ford Pickup F150

2003 GENERAL INFORMATION Driveline System - General Information - F150 Pickup