News Technical Service Bulletins

Lincoln 4WD Grinding Noise

Order Reprints
Lincoln 1

Note the IWE vacuum line locations (seen here in blue).

This bulletin applies to 2013-2018 Lincoln Navigator vehicles. Some vehicles equipped with 4WD might exhibit an intermittent grinding noise while driving in 2WD mode, most commonly on acceleration. This might be due to a loss of vacuum to the integrated wheel end (IWE) actuators and/or wear of the IWE components. To correct the condition, follow the service procedure steps to reprogram the transfer case control module (TCCM) and replace any worn vacuum and/or IWE components. 

The new TCCM calibration changes IWE operation at startup. When ambient temperature is above 32 degrees, the IWEs stay engaged regardless of a 4WD mode selection for about 0.5 miles. IWE engagement only occurs once per key cycle and is not reset when shifting between Park and Drive. The TCCM uses this strategy to delay vacuum use until vacuum-intensive engine startup has completed and sufficient vacuum is available to fully disengage IWEs.

  1. Reprogram the TCCM using the latest software version.

  2. Inspect the IWE vacuum hoses, checking for any disconnected or damaged hoses and correct as needed. 

  3. Replace the vacuum check valve located near the vacuum reservoir. 

  4. Disconnect the vacuum line to the IWEs at the vacuum solenoid. 

  5. Connect a hand vacuum pump to the IWE vacuum supply line and apply 20 in-Hg of vacuum.  If the vacuum drops more than 0.5 in-Hg per minute, proceed to Step 6. If not, connect the IWE vacuum supply line to the solenoid and proceed to Step 10.

  6. Using a hand vacuum pump, apply 20 in-Hg of vacuum to each IWE, one at a time, and monitor the vacuum gauge. If the vacuum drops more than 0.5 in-Hg per minute, proceed to Step 8. If not, proceed to Step 7.

  7. Replace the vacuum lines between the solenoid and the IWEs. Proceed to Step 12.

  8. Remove the IWE assembly from the affected wheel.

  9. Inspect the wheel bearing splines for damage or excessive wear. If damage/wear is found, replace the IWE assembly and wheel bearing. If no damage/wear is found, replace the IWE assembly.

  10. Test the IWE vacuum supply lines. Disconnect the vacuum supply line at the left or right IWE and connect a vacuum gauge to the supply line Start the engine and allow it to idle for 5 minutes to build vacuum. Connect the appropriate scan tool and enter TCCM datalogger. Active-command the vacuum solenoid Repeat this test on the opposite IWE vacuum supply line.

  11. Is the vacuum at both left and right supply lines greater than 10 in-Hg?  If yes, proceed to Step 12. If not, replace the vacuum lines between the solenoids and IWEs.

  12. Road test the vehicle for noise by performing heavy accelerations in 2WD, Engage the 4WD system to verify proper engagement/disengagement operation. If a grinding noise is present in 2WD mode that is not present in 4WD mode, proceed to Step 13. If not, the repair is complete.

  13. Remove the IWE assembly from the affected wheel.

  14. Inspect the wheel bearing splines. If the splines are damaged/worn, replace the IWE clutch ring and wheel bearing.

Lincoln 2

Using a hand vacuum pump, apply 20 in-Hg of vacuum to each IWE and monitor the gauge for vacuum drop. If vacuum drops more than 0.5 in-Hg per minute, remove the IWE assembly and inspect wheel bearing splines.

Lincoln 3

With engine idling to build vacuum and command the vacuum solenoid. The vacuum at both left and right supply lines should be greater than 10 in-Hg.

 

Related Articles

Lincoln Navigator Emits Grinding Noise

Transfer Case Grinding With Lincoln Navigator

Lincoln Brake Noise

You must login or register in order to post a comment.