The 1991 Mack Fdm has 3 NHTSA recall campaigns affecting an estimated 50,907 vehicles. Recall repairs are always free at any authorized dealer. Last updated July 5, 2026.
FUEL INJECTION SYSTEM RECONFIGURATION TO COMPLY WITH ENGINE EMISSION STANDARDS CAUSE HIGHER ENGINE VIBRATION LEVELS WHICH LEAD TO EARLY WEAR AND COMPLETE FAILURE OF THE SECONDARY THROTTLE RETURN MECHANISM.
IN THE EVENT THE PRIMARY THROTTLE RETURN FAILS, FAILURE OF THE SECONDARY THROTTLE RETURN SYSTEM WOULD NOT PROVIDE PROTECTION AGAINST LOSS OF THROTTLE CONTROL.
A NEW PRODUCTION SECONDARY THROTTLE RETURN SYSTEM CONFIGURATION WILL BE INSTALLED.
THE DRIVESHAFT TO THE FRONT DRIVING AXLE IS SECURED TO A BRACKET USING TWO PILLOW BLOCKS. THESE BLOCKS ARE OF INSUFFICIENT STRENGTH TO SUPPORT THE DRIVESHAFT AND COULD FAIL.
PILLOW BLOCK FAILURE ALLOWS THE DRIVELINE (JACKSHAFT)TO DROP DOWN ONTO THE ROADWAY AND CREATE A SAFETY HAZARD TO OTHER VEHICLES.
MACK WILL INSTALL THICKER PILLOW BLOCKS AND SUPPORT U-BOLTS.
THE ENGINE COOLING FAN BLADES MAY BREAK DUE TO INADEQUATE BLADE STRENGTH AROUND THE RIVETS THAT ATTACH THE BLADES TO THE FAN SPIDER.
IF COMPLETE FRACTURE OF THE FAN BLADE OCCURS, IT COULDBE PROPELLED OUTSIDE THE FAN SHROUD, INJURING PERSON(S) IN THE VICINITY OFTHE TRUCK.
AN IMPROVED FAN WILL BE INSTALLED ON THESE VEHICLES.
Recall, complaint, and investigation records from official NHTSA datasets (FLAT_RCL, FLAT_CMPL, FLAT_INV), synced weekly. Counts reflect NHTSA records for the 1991 Mack Fdm as of July 5, 2026. Complaint narratives are consumer-submitted and unverified. This page contains ads and affiliate links. Full methodology.