Ford F-150 1997–1999 — technical service bulletin
Bulletin 12590 · NHTSA communication 6091822 · issued Mar 1, 1999
Technical service bulletin
communication type
Power Train
component
1997–1999
model years
6
vehicle entries
Official summary
Some 4x4 vehicles may exhibit a moan noise from the front differential when the vehicle is operating in 4x2 mode and goes away when operating in 4x4 mode. *tt
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.