DEFINITION: The transfer case is not delivering engine torque to the front propeller shaft.

Review the Symptoms - Transfer Case and perform the necessary inspections.

Viscous coupling faulty

1. Inspect the transfer case fluid for being black. If the fluid is black, it is most likely caused by a viscous coupling failure.
2. Test for a faulty viscous coupling. Refer to Transfer Case Viscous Coupling Test .
3. Disassemble the transfer case. Refer to Transfer Case Disassemble in Transfer Case - BW 4473-NP3 Unit Repair.
4. Inspect the viscous coupling for leaking. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4473-NP3 Unit Repair.
5. Replace the viscous coupling if it is faulty. Refer to Transfer Case Assemble in Transfer Case - BW 4473-NP3 Unit Repair.

Planetary carrier faulty

1. Disassemble the transfer case. Refer to Transfer Case Disassemble in Transfer Case - BW 4473-NP3 Unit Repair.
2. Inspect for faulty planetary carrier components. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4473-NP3 Unit Repair.
3. Replace any faulty planetary carrier components. Refer to Transfer Case Assemble in Transfer Case - BW 4473-NP3 Unit Repair.