DIAGNOSIS A loud grinding or squealing noise from the rear is a worn or failed fuser drive gear. This is a known wear item on this model.
FIX The fuser assembly must be replaced. 1. Order HP part number CF378-67903 (the fuser kit). 2. Turn printer off, unplug, and let cool for 30 minutes. 3. Open the rear access door. 4. Pull the two blue tabs to release and lift out the entire fuser unit. 5. Insert the new fuser and close the door.
IF THAT DIDN'T WORK If noise persists, the main motor or gear train behind the fuser may be damaged, requiring professional service.
HEADS UP The fuser is extremely hot during operation. Always allow full cool-down before attempting removal. The grinding will get worse and will eventually cause paper jams.