1977 Mack DMM problems

Verdict · NHTSA data

Limited data — recalls on file

NHTSA has just 0 complaints on file for the 1977 Mack DMM — too few to judge reliability from owner reports alone — but 5 recall campaigns apply to this year, so any used example should have its VIN checked for completed recall work.

NHTSA complaints

Recalls

Investigations

Crash-involved

Fires reported

Injuries

Deaths

—

NCAP overall

Does the 1977 Mack DMM have recalls?

5 NHTSA recall campaigns on file. Recall repairs are free at franchised dealers.

79V133000EngineMay 31, 1979 · 23,000 units

Defect

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.

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.

78V210000BrakesOctober 3, 1978 · 19,370 units

Defect

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".

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.

78V172000SteeringAugust 8, 1978 · 13,800 units

Defect

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.

Remedy

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

77V173000EngineOctober 12, 1977 · 48,000 units

Defect

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.

Remedy

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

77V174000Seat BeltsOctober 12, 1977 · 6,591 units

Defect

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.

Remedy

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

1977 Mack DMM — common questions

Is the 1977 Mack DMM reliable?

The record is thin — 0 NHTSA complaints — so owner-report data can't strongly confirm reliability either way, though 5 recalls should be verified as completed.

Does the 1977 Mack DMM have recalls?

Yes — NHTSA lists 5 recall campaigns affecting the 1977 Mack DMM. Recall repairs are free at franchised dealers; check the VIN at nhtsa.gov/recalls to confirm the work was done.

Based on NHTSA ODI data through June 2026. Complaints are consumer-reported and unverified. Updated July 5, 2026.

Compiled by Sharon Ben-Moshe, Founder.

Does the 1977 Mack DMM have recalls?

1977 Mack DMM — common questions

Is the 1977 Mack DMM reliable?

Does the 1977 Mack DMM have recalls?

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