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TECHNICAL SERVICE BULLETIN
Electronic Shift On-The-Fly (ESOF) 4WD - Intermittent Grinding
Noise While Driving

21-2076
17 March 2021

This bulletin supersedes 20-2278. Reason for update: Missing or Incorrect Applications
Model:
Ford
2013-2018 F-150
Summary
This article supersedes TSB 20-2278 to update the Issue and Service Procedure.
Issue: Some 2013-2018 F-150 vehicles equipped with ESOF 4-wheel drive (4WD) may exhibit an
intermittent grinding noise while driving in 2-wheel drive (2WD) mode most commonly on acceleration.
ESOF can be identified as it does not have a 4WD AUTO (4A) position on the mode selector switch
(MSS). This may 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.
Action: Follow the Service Procedure steps to correct the condition on vehicles that meet the following
criteria:
• 2013-2018 F-150
• Equipped with ESOF 4WD (does not have a 4A position on the MSS)
• Customer concern of intermittent grinding noise in 2WD mode
NOTE: Part quantity refers to the number of that service part number required, which may be
different than the number of individual pieces. Service part numbers contain 1 piece unless
otherwise stated. "As Needed" indicates the part is required but the number may vary or is not a
whole number; parts can be billed out as non-whole numbers, including less than 1.
Parts
Part
Number

Description

W720613S439

Package Contains 4 Pieces, 2
Pieces Required Per Affected
Side

Caliper Anchor Plate Bolt (2015-2018
F-150)

W714743S439

Package Contains 4 Pieces, 2
Pieces Required Per Affected
Side

Caliper Anchor Plate Bolt (2013-2014
F-150)

N802827S100A

Package Contains 4 Pieces, 1
Piece Required Per Affected
Side

Front Half Shaft Nut (2016-2018 F-150
Built On Or After 3-Aug-2016)

N802827S100

Package Contains 4 Pieces, 1
Piece Required Per Affected
Side

Front Half Shaft Nut (2013-2016 F-150
Built On Or Before 2-Aug-2016)

W520215S441

Tie Rod Nut (2013-2014 F-150 Built On
Or Before 23-Dec-2014)

Quantity
1

1

1

1

1

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Package Contains 4 Pieces, 1
Piece Required Per Affected
Side
W520215S440

Package Contains 4 Pieces, 1
Piece Required Per Affected
Side

Tie Rod Nut (2014-2018 F-150 Built On
Or After 24-Dec-2014)

1

W520214S440

Package Contains 2 Pieces, 1
Piece Required Per Affected
Side

Upper Ball Joint Nut

7L1Z3C247-A

Package Contains 1 Piece, 1
Piece Required Per Affected
Side

1 Per
IWE Actuator (2013-2015 F-150 Built On
Affected Side
Or Before 11-Oct-2015)

HL1Z3C247-A

Package Contains 1 Piece, 1
Piece Required Per Affected
Side

1 Per
IWE Actuator (2015-2018 F-150 Built On
Affected Side
Or After 12-Oct-2015)

W706890S439

Package Contains 4 Pieces, 4
Pieces Required Per Affected
Side

Front Hub Bearing Bolts

1 Per
Affected Side

HL1Z3C247-B

Package Contains 1 Piece, 1
Piece Required Per Affected
Side

IWE Clutch Ring Kit

1 Per
Affected Side

3A788

-

1104

Package Contains 1 Piece, 1
Piece Required Per Affected
Side

BL3Z7A785-A

-

BL3Z7A785-B

-

FL3Z7A785-A

-

HL3Z7A785-A

-

HL3Z3C125-A

-

Vacuum Hose To IWE (2017-2018
Raptor)

1

FL3Z3C125-A

-

Vacuum Hose To IWE (2015-2018 F-150
Except Raptor)

1

XG-1-E1

-

Motorcraft® Premium Long-Life Grease

1

Check Valve - Refer To The Parts
Catalog For The VIN Specific Application

1

1 Per
Front Hub Bearing - Refer To The Parts
Affected Side
Catalog For The VIN Specific Application
Vacuum Lines (2013-2014 F-150 Except
Raptor)

1
1

Vacuum Lines (2013-2014 Raptor)
Vacuum Lines (2015-2018 F-150 Except
Raptor)

1
1

Vacuum Lines (2017-2018 Raptor)

As Needed

Warranty Status: Eligible under provisions of New Vehicle Limited Warranty (NVLW)/Service Part
Warranty (SPW)/Special Service Part (SSP)/Extended Service Plan (ESP) coverage. Limits/policies/prior
approvals are not altered by a TSB. NVLW/SPW/SSP/ESP coverage limits are determined by the
identified causal part and verified using the OASIS part coverage tool.
Labor Times
Description

Operation
Time
No.
212076A

0.8
Hrs.

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2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both IWEs
(Pass) Road Test (Pass) (Can Be Claimed With Operations L, M And N) (Do Not
Use With Any Other Labor Operations Outside Of This Article)
2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both IWEs
(Fail) Apply Vacuum Directly To Each IWE (One Fail) Remove One IWE, Inspect
Wheel Bearing Splines (Pass) Replace One (1) IWEs (Can Be Claimed With
Operations L, M And N) (Do Not Use With Any Other Labor Operations Outside Of
This Article)

212076B

1.1
Hrs.

2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both IWEs
(Fail) Apply Vacuum Directly To Each IWE (One Fail) Remove IWE, Inspect Wheel
Bearing Splines (One Fail) Replace One (1) Wheel Bearing And One (1) IWE (Can
Be Claimed With Operations L, M And N) (Do Not Use With Any Other Labor
Operations Outside Of This Article)

212076C

1.2
Hrs.

2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both IWEs
(Fail) Apply Vacuum Directly To Each IWE (Both Fail) Remove Both IWEs, Inspect
Wheel Bearing Splines (Both Pass) Replace Both (2) IWEs (Can Be Claimed With
Operations L, M And N) (Do Not Use With Any Other Labor Operations Outside Of
This Article)

212076D

1.8
Hrs.

2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both IWEs
(Fail) Apply Vacuum Directly To Each IWE (Both Fail) Remove IWEs, Inspect Wheel
Bearing Splines (One Fail) Replace One (1) Wheel Bearing And Both (2) IWE’s (Can
Be Claimed With Operations L, M And N) (Do Not Use With Any Other Labor
Operations Outside Of This Article)

212076E

1.9
Hrs.

2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both IWEs
(Fail) Apply Vacuum Directly To Each IWE (Both Fail) Remove IWEs, Inspect Wheel
Bearing Splines (Both Fail) Replace Both (2) Wheel Bearings And Both (2) IWEs
(Can Be Claimed With Operations L, M And N) (Do Not Use With Any Other Labor
Operations Outside Of This Article)

212076F

2.1
Hrs.

2013-2018 F-150 4X4:Inspect, Replace Check Valve, Apply Vacuum To Both IWEs
(Both Pass) Road test (FailOne Side) Remove IWE, Inspect Wheel Bearing Splines
(Pass) Replace One (1) IWE Clutch Ring (Can Be Claimed With Operations L, M
And N) (Do Not Use With Any Other Labor Operations Outside Of This Article)

212076G

1.6
Hrs.

2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both IWEs
(Both Pass) Road test (Fail Both Sides) Remove Both IWEs, Inspect Wheel Bearing
Splines (Both Pass) Replace Both (2) IWE Clutch Rings (Can Be Claimed With
Operations L, M And N) (Do Not Use With Any Other Labor Operations Outside Of
This Article)

212076H

2.3
Hrs.

2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both (2)
IWEs (Both Pass) Road Test (Fail One Side) Remove IWE, Inspect Wheel Bearing
Splines (Fail One Side) Replace One (1) Wheel Bearing And One (1) IWE Clutch
Ring (Can Be Claimed With Operations L, M And N) (Do Not Use With Any Other
Labor Operations Outside Of This Article)

212076J

1.8
Hrs.

2013-2018 F-150 4X4: Inspect, Replace Check Valve, Apply Vacuum To Both (2)
IWEs (Both Pass) Road test (Fails Both Sides) Remove Both IWEs, Inspect Wheel
Bearing Splines (Fail Both Sides) Replace Both (2) Wheel Bearings And Both (2)
IWE Clutch Rings (Can Be Claimed With Operations L, M And N) (Do Not Use With
Any Other Labor Operations Outside Of This Article)

212076K

2.6
Hrs.

2013-2018 F-150 4X4: Additional Time Use Scan Tool To Active Solenoid And
Measure Vacuum At Both IWEs (Can Be Claimed With Operations A-K)

212076L

0.3
Hrs.

2013-2018 F-150 4X4: Additional Time To Be Used When Vacuum Harness
Replacement Is Necessary (Can Be Claimed With Operations A-K)

212076M

0.5
Hrs.

2017-2018 F-150 4X4: Additional Time To Be Used When TCCM Reprogramming Is
Necessary (Can Be Claimed With Operations A-K)

212076N

0.2
Hrs.

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Repair/Claim Coding
Causal Part:

3C247

Condition Code: D4

Service Procedure
1. Does the vehicle have a MSS that only includes 2H, 4H and 4L positions (does not include 4A)? (Figure
1)
(1). Yes - proceed to Step 2.
(2). No - this article does not apply. Refer to the Workshop Manual (WSM) or other service articles for
normal diagnostics.
Figure 1 - Example of MSS without 4A selection

2. For 2017-2018 vehicles only, reprogram the TCCM using the latest version of the appropriate Ford
scan tool.
NOTE: The new TCCM calibration changes IWE operation at start up. When ambient temperature is
above 0°C (32°F) the IWEs stay engaged regardless of a 4WD mode selection for approximately 0.8
km (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 vacuumintensive engine startup has completed and sufficient vacuum is available to fully disengage
IWEs.
3. Inspect the IWE vacuum hoses. Refer to Workshop Manual (WSM), Section 308-07A. Are there any
disconnected or damaged vacuum hoses? (Figure 2)
(1). Yes - reconnect or replace the vacuum hose as required. Refer to WSM, Section 308-07A.
(2). No - proceed to Step 4.
Figure 2

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4. Replace the vacuum check valve located near the vacuum reservoir. Refer to WSM, Section 308-07A.
5. Disconnect the vacuum line to the IWEs at the vacuum solenoid.
6. Connect a hand vacuum pump to the IWE vacuum supply line and apply 508 mm (20 in) Hg of vacuum.
Does the vacuum drop more than 12.5 mm (0.5 in) Hg per minute? (Figure 3)
(1). Yes - proceed to Step 7.
(2). No - connect the IWE vacuum supply line to the solenoid and proceed to Step 11.
Figure 3

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7. Using a hand vacuum pump, apply 508 mm (20 in) Hg of vacuum to each IWE, one at a time, and
monitor the vacuum gauge. Does the vacuum drop more than 12 mm (0.5 in) Hg per minute? (Figure 4)
(1). Yes - proceed to Step 9.
(2). No - proceed to Step 8.
Figure 4

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8. Replace the vacuum lines between the solenoid and IWEs. Refer to the WSM, Section 308-07A.
Proceed to Step 13.
9. Remove the IWE assembly from the affected wheel. Refer to WSM, Section 308-07A.
10. Inspect the wheel bearing splines for damage or excessive wear. Is wheel bearing spline damage or
excessive wear present?
(1). Yes - replace the IWE assembly and wheel bearing. Refer to WSM, Section 308-07A and 204-01B.
Proceed to Step 13.
(2). No - replace the IWE assembly. Refer to WSM, Section 308-07A. Proceed to Step 13.
11. Test the IWE vacuum supply lines.
(1). Disconnect the vacuum supply line at the left or right IWE and connect a vacuum gauge to the
supply line as shown in Figure 5.
(2). Start the engine and allow it to idle for 5 minutes to build vacuum.
(3). Connect the appropriate Ford diagnostic scan tool and enter TCCM data logger.
(4). Active command the vacuum solenoid.
• Command IWE_OS # to No.

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(5). Repeat this test on the opposite IWE vacuum supply line.
Figure 5

12. Is the vacuum at both left and right supply lines greater than 254 mm (10 in) Hg?
(1). Yes - proceed to step 13.
(2). No - replace the vacuum lines between the solenoid and IWEs. Refer to the WSM, Section 30807A. Proceed to Step 13.
13. Road test the vehicle for noise by performing heavy accelerations in 2WD. Engage the 4WD system to
verify proper engagement/disengagement quality. Is a grinding noise present in 2WD mode that is not
present in 4WD mode?
NOTE: When ambient temperature is above 0°C (32°F) the IWEs stay engaged regardless of a 4WD
mode selection for approximately 0.8 km (0.5 miles).
(1). Yes - proceed to Step 14.
(2). No - repair is complete.
14. Remove the IWE assembly from the affected wheel. Refer to WSM, Section 308-07A.
15. Inspect the wheel bearing splines. Is wheel bearing spline damage present?

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(1). Yes - replace the IWE clutch ring and wheel bearing. Refer to WSM, Sections 308-07A and 20401B.
(2). No - replace the IWE clutch ring. Refer to WSM, Section 308-07A.

© 2021 Ford Motor Company
All rights reserved.
NOTE: The information in Technical Service Bulletins is intended for use by trained, professional technicians with the knowledge,
tools, and equipment to do the job properly and safely. It informs these technicians of conditions that may occur on some vehicles, or
provides information that could assist in proper vehicle service. The procedures should not be performed by "do-it-yourselfers". Do
not assume that a condition described affects your car or truck. Contact a Ford or Lincoln dealership to determine whether the
Bulletin applies to your vehicle. Warranty Policy and Extended Service Plan documentation determine Warranty and/or Extended
Service Plan coverage unless stated otherwise in the TSB article. The information in this Technical Service Bulletin (TSB) was
current at the time of printing. Ford Motor Company reserves the right to supersede this information with updates. The most recent
information is available through Ford Motor Company's on-line technical resources.

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