Locking Hubs

Manual Locking Hub Components

Knob

• The locking hub knob has two positions: free/unlock and lock.

• In the free/unlock position, the hub rotates independently of the axle shaft.

• When turned to the lock position, the hub and axle shaft engage, allowing power from the differential to transfer to the wheels.

• Changing the knob position requires the vehicle to be stopped, and the driver must manually adjust it.

• In the locked position:

  • The knob rotates with the hub.

  • The hub is engaged to the axle shaft, enabling torque transfer.

Clutch

• The manual locking hub clutch moves when the knob is turned to the lock position, engaging the hub to the axle shaft.

• When the knob is turned to the free/unlock position, the clutch slides back, releasing the hub from the axle shaft.

• This allows the wheels to rotate independently of the axle shafts.

• The manual locking hub clutch:

  • Applies pressure to the hubs.

  • Engages to lock the components together.

Hub Body

• The hub body houses the knob and clutch, forming a complete locking hub assembly.

• This assembly bolts to the hub of the front brake rotor on the vehicle.

• The metal hub body is usually painted or treated to resist corrosion.

• A gasket or O-ring seals the hub body to the brake rotor, preventing leaks and contamination.

Automatic Locking Hub Components

Vacuum Reservoir, Hoses, and Check Valve

• Engine vacuum is stored in the vacuum reservoir, which supplies the IWE (Integrated Wheel End) system.

• A check valve separates the IWE system from other engine components, ensuring the IWE remains disengaged if another system experiences a vacuum leak.

• Hoses connect the IWEs, left and right steering knuckles, and the vacuum reservoir.

• Vent hoses on the IWE allow the diaphragm to expand and contract during operation.

• Together, the vacuum reservoir, hoses, and check valve maintain the correct pressure within the automatic locking front hub system.

IWE Solenoid

• Switched battery voltage provides power to the IWE solenoid.

• The control module supplies a ground to the solenoid when the driver selects 2WD high.

• In 2WD, engine vacuum passes through the solenoid to disengage the IWEs.

• When the driver selects 4WD, the control module releases the ground, allowing the existing vacuum to exhaust from the IWEs through the solenoid.

IWE Spring-loaded Vacuum Hubs

• IWE (Integrated Wheel End) spring-loaded vacuum hubs include:

  • An outer housing that bolts to the steering knuckle

  • A vacuum diaphragm

  • An internal spring

  • An inner collar with internal splines

• The inner collar splines onto the outer CV joint housing.

• When vacuum exhausts from the IWE, the internal spring pushes the collar to engage the splines on the wheel hub, connecting the axle shaft to the wheel hub.

• If a vacuum leak occurs while in 2WD, a grinding noise may occur as the collar attempts to engage the hub without torque from the transfer case.

Front Axle Disconnect

Vacuum Disconnect

• When four-wheel drive is selected, a vacuum switch on the transfer case opens.

• The switch directs engine vacuum to the vacuum shift servo, which pulls the shift fork.

• The sliding shift fork engages the shift collar, connecting the intermediate axle shaft to the outer axle shaft.

• This locks both axle shaft sections together, allowing power from the transfer case to be transmitted to the front wheels.

Electronic Disconnect

• The electric disconnect engages when the driver selects four-wheel drive.

• The transfer case control module signals the electric motor actuator to extend the plunger.

• The plunger moves the clutch fork and sleeve, locking the two axle shafts together.

• When two-wheel drive is selected, the control module signals the actuator to retract the plunger.

• This slides the clutch fork back, disconnecting the two shafts.