VIN 1M2AA13Y7TW053736

ON CERTAIN CHASSIS BUILT WITH LNG ENGINES, THE NEXGEN LNG TANK'S PRIMARY AND SECONDARY RELIEF VALVES COULD FAIL TO OPEN AND RELIEVE TANK PRESSURE.

THIS COULD CAUSE ICE BUILDUP ON THE DISCHARGE SIDE OF THE PRIMARY AND SECONDARY PRESSURE SYSTEM ALLOWING THE RELIEF SYSTEM TO FREEZE AND BECOME BLOCKED RESULTING IN OVER PRESSURIZATION OF THE LNG TANKS CREATING THE RISK OF CATASTROPHIC TANK RUPTURE WHICH COULD CAUSE SERIOUS INJURY OR DEATH.

DEALERS WILL RETROFIT THE LNG TANKS WITH A NEW PRIMARY RELIEF VALVE PIPE AWAY TUBE AND A NEW VENTILATED SHROUD. THE RECALL BEGAN APRIL 6, 2004. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT MACK AT 1-610-709-3337.

THE U-JOINT BEARING STRAP BOLTS WERE NOT PROPERLY TIGHTENED DURING ASSEMBLY.

INSUFFICIENT TORQUE CAN LEAD TO A BROKEN STRAP. IF THE STRAP BREAKS, THE DRIVESHAFT WOULD WOBBLE, POSSIBLY RESULTING IN SEPARATION. SUCH WOBBLING OR SEPARATION WOULD RESULT IN DAMAGE TO OTHER COMPONENTS OF THE VEHICLE AND ANY LOOSE FRAGMENT COULD FALL TO THE ROADWAY PRESENTING A HAZARD TO FOLLOWING VEHICLES.

DEALERS WILL INSTALL A NEW U-JOINT BEARING STRAP BOLTS.

VEHICLE DESCRIPTION: HEAVY DUTY TRUCKS EQUIPPED WITH DESIGN LEVEL 1, ROCKWELL FF980 SERIES FRONT AXLE. THE FRONT AXLE HUB FLANGE CAN DEVELOP CRACKS DUE TO HIGH STRESS LEVELS.

CRACKS IN A HUB FLANGE CAN RESULT IN A WHEEL SEPARATION.

DEALERS WILL REMOVE AND REPLACE THE FRONT HUBS WITH AN IMPROVED DESIGN LEVEL 2 HUB.