Ford F-150 2013–2018 — technical service bulletin
Bulletin TSB 21-2076 · NHTSA communication 10189784 · issued Mar 18, 2021
Technical service bulletin
communication type
Power Train
component
2013–2018
model years
6
vehicle entries
Official summary
Some 2013-2018 F-150 vehicles equipped with electronic shift on-the-fly (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.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.