Model year record

1977 MACK DMM

5 recall campaigns on file for this model year. No owner complaints on file.

Recalls

Recall campaignNHTSA 79V133000

Engine and engine cooling: engine

Component
Engine and engine cooling: engine
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
23,000
Reported to NHTSA
1979-05-31
Owners notified
1979-11-02

Defect description

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.

Manufacturer remedy

DEALER WILL INSTALL A SHIELD FOR THE HEADS OF THE FOUR CAPSCREWS, ALONG WITH STRONGER SAE 8 GRADE 8 CAPSCREWS, IF NECESSARY, AT NO COST TO OWNER.

Recall campaignNHTSA 78V210000

Service brakes, air: antilock: interconnecting assembly(wiring)

Component
Service brakes, air: antilock: interconnecting assembly(wiring)
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
19,370
Reported to NHTSA
1978-10-03
Owners notified
1978-11-07

Defect description

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".

Manufacturer remedy

DEALER WILL INSTALL NEW WHEEL SPEED SENSORS THAT INCORPORATE IMPROVED WIRING AND THE PRESENT BOGIE ANTI-WHEEL LOCK SYSTEM WILL BE CHANGED TO AN AXLE-TO-AXLE SYSTEM FOR IMPROVED RELIABILITY.

Recall campaignNHTSA 78V172000

Steering: linkages: knuckle: spindle: arm

Component
Steering: linkages: knuckle: spindle: arm
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
13,800
Reported to NHTSA
1978-08-08
Owners notified
1979-02-22

Defect description

THE EXISTING CROSS STEERING ARMS MAY HAVE INSUFFICIENT FATIGUE LIFE IN THE NECK AREA. THIS IS NEAR THE BOSS FOR THE CROSS STEERING TUBE BALL JOINT CONNECTION. FAILURE OF EITHER OF THE CROSS STEERING LEVERS COULD LEAD TO LOSS OF STEERING CONTROL OF THE RIGHT FRONT WHEEL.

Manufacturer remedy

THE DEALER WILL INSPECT AND, IF NECESSARY, INSTALL CROSS STEERING ARMS OF IMPROVED DESIGN AND GREATER STRENGTH.

Recall campaignNHTSA 77V174000

Seat belts: front: anchorage

Component
Seat belts: front: anchorage
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
6,591
Reported to NHTSA
1977-10-12
Owners notified
1978-08-23

Defect description

THE INVOLVED VEHICLES DO NOT CONFORM TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 209, "SEATBELT ASSEMBLIES". ALTHOUGH THE SEATBELTS IN QUESTION PERFORMED MARGINALLY WITH RESPECT TO THE 5000 LB. LOAD REQUIREMENT, ADDITIONAL TESTING CONFIRMED THAT THE ANCHOR COULD FAIL, ALLOWING EITHER THE ANCHOR TO SLIP OVER THE HOLD-DOWN NUT OR THE ANCHOR TO SEPARATE INTO TWO PIECES.

Manufacturer remedy

DEALER WILL INSPECT AND, IF NECESSARY, REPLACE SEAT BELT ASSEMBLIES WITHOUT CHARGE TO OWNER.

Recall campaignNHTSA 77V173000

Engine and engine cooling: cooling system: fan

Component
Engine and engine cooling: cooling system: fan
Manufacturer
MACK TRUCKS, INCORPORATED
Vehicles affected
48,000
Reported to NHTSA
1977-10-12
Owners notified
1978-03-23

Defect description

THE FLEX BLADE FANS ON THE INVOLVED VEHICLES MAY DEVELOP CRACKS IN THE LAMINATED STIFFENER AS A RESULT OF FATIGUE DURING OPERATION. IF SUCH A CONDITION EXISTS AND THE CRACKS GO UNDETECTED, CONTINUED OPERATION COULD CAUSE PIECES OF THE STIFFENER TO BREAK OFF.

Manufacturer remedy

DEALER WILL REPLACE THE ORIGINAL FAN WITH A STEEL FIXED BLADE FAN, FREE OF CHARGE.

Owner complaints

A complaint is one person's report to a federal agency. It is not a finding.

No complaints recorded for this model year.

Safety recall repairs are provided free of charge by franchised dealers, regardless of vehicle age or mileage. This page displays aggregated data for the model year. To check recall status for a specific vehicle, search its VIN at nhtsa.gov.