1978 Mack Rwl

ENGINE AND ENGINE COOLING:ENGINE

THE POSSIBILITY EXISTS THAT THE ALUMINUM ENGINE REAR SUPPORT BRACKETS MAY FAIL DUE TO METAL FATIGUE. THIS TYPE OF FAILURE WOULD ALLOW THE ENGINE AND TRANSMISSION ASSEMBLY TO DISLOCATE DOWNWARD. THIS WILL RESULT IN THROTTLE CONTROL LOSS WITH THE ENGINE OPERATING CONTINUOUSLY IN THE MID TO UPPER RANGE OF THE GOVERNED SPEED RANGE.

SERVICE BRAKES, AIR:ANTILOCK:INTERCONNECTING ASSEMBLY(WIRING)

DELAYS OF UP TO ABOUT 2 SECONDS MAY EXIST IN THE BRAKE APPLICATION TIMES TO THE BRAKES ON THE BOGIE AXLES IN THE PRESENCE OF CERTAIN TYPES OF WHEEL SPEED SENSOR SIGNAL DISCONTINUITIES OR DISTORTIONS THAT MAY OCCUR AS A RESULT OF SENSOR WIRE FAILURE. THIS CONSTITUTES A NON-COMPLIANCE TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 121, "AIR BRAKE SYSTEMS".

ELECTRICAL SYSTEM:WIRING

A SHORT CIRCUIT COULD OCCUR DUE TO CHAFING OR WIRE DISCONNECTION IN THE BOX.

STEERING: STEERING WHEEL/HANDLE BAR

IT HAS BEEN DETERMINED THAT TWO SCREWS THAT ARE PART OF THE BEARING ASSEMBLY LOCATED AT THE CAB DASH SHEET MAY NOT HAVE BEEN TIGHTENED PROPERLY. AS A RESULT, THE UPPER STEERING SHAFT MAY BE FREE TO "FLOAT" THROUGHOUT MUCH OF ITS LENGTH WHICH MAY RESULT IN INADEQUATE ENGAGEMENT IN THE SLIP SPLINES OF THE LOWER STEERING SHAFT. AXLE ARTICULATION COULD RESULT IN DISENGAGEMENT OF THE LOWER STEERING SHAFT SLIP SPLINES.

ENGINE AND ENGINE COOLING:ENGINE

IN THE EVENT OF TURBOCHARGER COMPRESSOR WHEEL FAILURE, ONE OR MORE OF THE FOUR CAPSCREWS THAT HOLD THE TURBOCHARGER TOGETHER MAY BE STRUCK BY PARTS OF THE COMPRESSOR WHEEL, RESULTING IN THE CAPSCREWS BEING DAMAGED. IF THESE CAPSCREWS ARE DAMAGED TO THE POINT THAT THEY ALLOW THE COMPRESSOR BACK PLATE TO DISLOCATE FROM THE TURBOCHARGER BEARING HOUSING, ENGINE LUBRICATING OIL MAY BE ALLOWED TO ESCAPE UNDER PRESSURE, CONTACTING THE ENGINE EXHAUST MANIFOLD SECTIONS OR TURBOCHARGER TURBINE HOUSING.