Download FORD: 1983-1990 BRONCO II 1983-1995 RANGER 1991-1994 EXPLORER WHEEL END NOISE (BUZZING) IN 4X2, AFTER ISSUE UNLOCKING HUBS, SHORTLY AFTER 4X4 system diagnosis can be difficult at times due FOUR-WHEEL DRIVE USAGE: to system complexities. •Noise concerns in two-wheel drive shortly after ACTION shifting from four-wheel drive and unlocking hubs, can occur if one of the hublocks fails to For general system operation and diagnosis: Refer disengage. As the vehicle moves forward, the one to TSB Article No. 92-1-8. (1) hublock that has failed to disengage will rotate its axle shaft through the differential and attempt For specific automatic lock hub diagnosis and to rotate the other axle shaft in the opposite service: Refer to this article. direction. This is called differential motoring HUBLOCK DIAGNOSTICS torque. As this torque attempts to turn the other axle shaft through the differential gears, that WHEEL END CONTAMINATION: shaft’s hublock will attempt to engage which will •All compact vehicle hublocks have an O-ring seal result in a ratcheting or buzzing noise. between the hublock and wheel hub to prevent •This type of noise concern is usually found on contamination. Whenever the hublock is removed, axles that have incorrect front axle differential the O-ring seal should be checked for damage. lubricant or very few 4X4 miles on them. •If contamination is found in the wheel end, the •Verify that the front axle differential lubricant is path must be determined and corrected. Path F1TZ-19580-A. If incorrect lubricant is detected, possibilities are through the hublock seal, the extract the old lubricant using a suction gun. wheel bearing seals or the axle spindle seals. NOTE BREAKING THE CARRIER SEAL IS NOT A RECOMMENDED METHOD OF EXTRACTING THE LUBRICANT. 1. Refill the front axle with 56 oz (1.66 L) of lubricant F1TZ-19580-A using a suction gun. 2. As the front axle accumulates 100-200 miles (161-322 km) of locked hublock operation, the axle will break-in, thus reducing the amount of differential motoring torque significantly. 3. If a front axle requires breaking in, refer to the Front Axle Break-In Procedure in this article.