Initial Inspection and Diagnostic Overview

Inspection and Verification

Certain axle and driveline symptoms are also common to the engine, transmission, wheel bearings, tires, and other parts of the vehicle. For this reason, be sure that the cause of the trouble is in the axle before disassembling, adjusting or repairing the axle.

Certain driveshaft vibration symptoms are common to the Front Accessory Drive (FEAD), the engine, transmission or tires. Be sure the cause is the driveshaft before repairing or installing a new driveshaft.

Certain symptoms may be caused by Traction-Lok differentials. Check the vehicle certification label and axle identification tag to determine the type of differential.

Noise Acceptability

NOTE: A gear-driven unit will produce a certain amount of noise. Some noise is acceptable and audible at certain speeds or under various driving conditions such as a newly paved blacktop road. Slight noise is not detrimental to the operation of the axle and is considered normal.

With the Ford Traction-Lok@ differential, slight chatter noise on slow turns after extended highway driving is considered acceptable and has no detrimental effect on the locking differential function.

Universal Joint (U-Joint) Inspection
Place the vehicle on a frame hoist and rotate the driveshaft by hand. Install a new U-joint if it shows signs of seizure, excessive wear, or incorrect seating.

Inspection For Bent Rear Axle Housing
1. Raise and support the vehicle. Allow the rear axle to be freely suspended.





2. Use white chalk or paint to mark a vertical line on the center of each rear tire.





3. Adjust both wheels so that the markings face the front of the vehicle. With a tape measure, measure the distance between the marks and record this reading (front reading).





4. Rotate the rear wheels so the markings are directly underneath the vehicle. Measure the distance between the marks and record this reading (bottom reading).





5. Rotate the rear wheels so the markings face the rear of the vehicle. Measure and record the distance between the marks (rear reading).
6. Compare the front and the rear readings (Steps 3 and 5) to find the toe-in or toe-out condition.
^ Toe-in occurs when the front measurement is less than the rear measurement.
^ Toe-out occurs when the rear measurement is less than the front measurement.
7. To determine camber, find the average of the front and the rear measurements (Steps 3 and 5). Subtract the bottom reading (Step 4) from this number.
8. Positive (+) camber is when the bottom reading is less than the average of the front and rear readings. Negative (-) camber is when the bottom reading is greater than the average of the front and rear readings.
9. The results of the calculations in Steps 6 and 7 must conform to the following specifications:
^ Toe-in: 0 - 1/16 inch.
^ Toe-out: 0 - 3/16 inch.
^ Camber: 0 � 5/32 inch.
If the differential housing does not meet these specifications, install a new differential housing.