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Service bulletin SB-21-5035

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10027767
Published by NHTSA2009-02-03
Manufacturer's numberSB-21-5035
Manufacturer's date2008-10-17
NHTSA componentENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN

NHTSA's summary

MACK TRUCK: REVISED FAN HUB MOUNTING BOLT TORQUE. FOR THIS APPLICATION ONLY, THE FAN HUB MOUNTING STUD MATERIAL PROPERTIES AND LENGTH HAVE BEEN CHANGED TO 45MM (WAS 40MM) TO ENSURE FULL NUT ENGAGEMENT. MODEL YEARS UNKNOWN. *PE

The document

No address for NHTSA's copy can be built for this communication. Ask the dealer for it by the manufacturer's number.

Components

Engine, Cooling fan, Cooling system

Vehicles listed
MACK CHU2006 to 2008
MACK GU2006 to 2009

Listing a model year does not mean every vehicle of it is concerned: the document says which.