Ford F-250 SD 2021 — technical service bulletin
Bulletin SSM 50032 · NHTSA communication 10200999 · issued Aug 13, 2021
Technical service bulletin
communication type
Power Train
component
2021
model years
4
vehicle entries
Official summary
Some 2021 F-250 vehicles equipped with a 6R100 transmission, four-wheel drive (4WD), 3.73 rear axle ratio, and built on or after 01-Feb-2021 may exhibit a metallic grinding noise from the rear of the vehicle under light acceleration between 23-33 mph (37-53 Km/h). The noise is most prevalent in 3rd and 4th gear when the vehicle is warm. This may be due to normal driveline noise transmitting through the driveshaft. To correct the condition, replace the rear axle drive pinion flange using service part number HC3Z-4851-A. Also, replace the rear pinion seal. Refer to Workshop Manual (WSM), Section
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.