1977 MACK U
8 recalls, 0 complaints - 27 TSBs
79V133000 May 31, 1979
ENGINE AND ENGINE COOLING:ENGINE
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... Read more
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.
79V082000 Apr 3, 1979
STEERING: STEERING WHEEL/HANDLE BAR
Defect Description
AN IMPROPER PINCH BOLT AND NUT MAY HAVE BEEN USED IN THE CLAMPING OF THE STEERING SHAFT TO THE STEERING GEAR INPUT SHAFT. DUE TO CLAMPING FORCE LOADS APPLIED AT THE BOLT, THE NUT COULD YIELD, RESULTING IN LOOSENESS OF THE INPUT SHAFT YOKE. SHOULD THIS CONDITION GO UNNOTICED, SPLINE WEAR COULD CAUSE... Read more
Remedy
VEHICLES WILL BE INSPECTED AND, IF NECESSARY, THE CORRECT FASTENERS WILL BE INSTALLED AT NO CHARGE TO OWNER.
79V017000 Jan 12, 1979
SUSPENSION:MULTIPLE AXLE
Defect Description
A CASTING DEFICIENCY EXISTS IN THE LOWER SECTION OF THE CAPS RESULTING IN A REDUCTION IN THE THICKNESS OF THE MATERIAL. FAILURE OF A CAP CAN ALLOW THE END OF THE REAR SPRING TO DETACH FROM THE AXLE HOUSING.
Remedy
DEALER WILL INSPECT AND, IF NECESSARY, REPLACE ANY OF THE SPRING INSULATOR CAPS FOUND TO BE DEFECTIVE. THIS WILL BE DONE AT NO COST TO OWNER.
78V210000 Oct 3, 1978
SERVICE BRAKES, AIR:ANTILOCK:INTERCONNECTING ASSEMBLY(WIRING)
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... Read more
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.
78V031000 Feb 9, 1978
SUSPENSION:MULTIPLE AXLE
Defect Description
THE TEE BRACKET, WHICH IS MOUNTED ON THE FRONT AXLE OF THE BOGIE, MAY FAIL DUE TO VIBRATION BROUGHT ON BY ROAD SURFACE IRREGULARITIES. BRACKET FAILURE WOULD LEAVE THE TEE BRACKET UNSUPPORTED AND CAUSE BROKEN HOSE CONNECTOR FITTINGS. THIS WOULD RESULT IN AUTOMATIC APPLICATION OF THE SPRING EMERGENCY ... Read more
Remedy
THE DEALER WILL REPLACE THE DEFECTIVE BRACKET WITH A REDESIGNED VERSION.
77V205000 Nov 21, 1977
SUSPENSION:REAR:SPRINGS:LEAF SPRING ASSEMBLY:HANGER/BRACKET
Defect Description
A DEFICIENCY EXISTS IN THE WELDS SECURING THE REAR SPRING INSULATOR BRACKET TO THE AXLE HOUSING. THIS IS DUE TO IMPROPER POSITIONING OF THE WELD, IN RELATIONSHIP TO THE BRACKET AND AXLE HOUSING. FAILURE OF THE WELDS WOULD CAUSE SEPARATION OF THE SPRING INSULATOR BRACKET AND THE AXLE HOUSING, RESULTI... Read more
Remedy
DEALER WILL REWELD THE INSULATOR SPRING BRACKET AT NO COST TO OWNER.
77V174000 Oct 12, 1977
SEAT BELTS:FRONT:ANCHORAGE
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 ... Read more
Remedy
DEALER WILL INSPECT AND, IF NECESSARY, REPLACE SEAT BELT ASSEMBLIES WITHOUT CHARGE TO OWNER.
77V173000 Oct 12, 1977
ENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN
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.
Remedy
DEALER WILL REPLACE THE ORIGINAL FAN WITH A STEEL FIXED BLADE FAN, FREE OF CHARGE.
No complaints found for this vehicle.
Technical Service Bulletins, 1977 MACK U
27 manufacturer communications from 22 unique bulletins. TSBs describe known problems and recommended fixes from the manufacturer.
Most Affected Components
| Component | Bulletins |
|---|---|
| 060000 ENGINE AND ENGINE COOLING | 12 |
| 110000 ELECTRICAL SYSTEM | 4 |
| 100000 POWER TRAIN | 4 |
| 180000 VEHICLE SPEED CONTROL | 2 |
| 980000 UNKNOWN OR OTHER | 2 |
| 251000 ELECTRONIC STABILITY CONTROL:AUTOMATIC (ASC) | 1 |
| 020000 SUSPENSION | 1 |
| 350000 EQUIPMENT | 1 |
KC-750
Jun 28, 2022
060000 ENGINE AND ENGINE COOLING
US10 Emission Engines - Diagnostic Trouble Code ( DTC ) SPN 1231 FMI 9 Troubleshooting.
KC-745
Jun 22, 2022
100000 POWER TRAIN
Automated Manual Transmission ( AMT ) I-Shift / mDRIVE - Ribbon Harness Replacement - Speed Sensor Bolts, Possible Fault Codes P1058 - 21 Or MID 130 PID 161 FMI 1
KC-2112
Jun 21, 2022
110000 ELECTRICAL SYSTEM
Programming Failure - Chassis With Cummins Engine And An Allison Transmission
KC-2112
Jun 21, 2022
100000 POWER TRAIN
Programming Failure - Chassis With Cummins Engine And An Allison Transmission
KC-2112
Jun 21, 2022
060000 ENGINE AND ENGINE COOLING
Programming Failure - Chassis With Cummins Engine And An Allison Transmission
KC-2143
Jun 21, 2022
180000 VEHICLE SPEED CONTROL
(Back Office) - Cruise Control Inoperative After Updating Software VECU5 Without ESP Package (UESP).
KC-2116
May 26, 2022
060000 ENGINE AND ENGINE COOLING
NOx Sensor Troubleshooting Guide - US10+OBD13 And Newer Emissions
KC-2131
May 26, 2022
060000 ENGINE AND ENGINE COOLING
USE FOR NEW VEHICLES (US21+OBD22 Emissions) - Intermittent Diagnostic Trouble Codes U02A3, U029D, U029E
KC-2158
May 26, 2022
060000 ENGINE AND ENGINE COOLING
Selective Catalytic Reduction (SCR) Muffler Troubleshooting Guide - US10+OBD13 And Newer Emissions
KC-2171
May 26, 2022
060000 ENGINE AND ENGINE COOLING
Temperature Sensor Troubleshooting Guide - US10+OBD13 And Newer
KC-2165
May 26, 2022
060000 ENGINE AND ENGINE COOLING
DEF Pump Troubleshooting Guide - US10+OBD13 And Newer Emissions
KC-714
May 25, 2022
060000 ENGINE AND ENGINE COOLING
Mack Chassis - Diagnostic Trouble Codes ( DTC's ) - P020113, P020213, P020313, P020413, P020513, P020613, Cylinders 1 Through 6 Injector A Open Circuit
KC-699
May 24, 2022
110000 ELECTRICAL SYSTEM
Mack Chassis - Bendix Vendor Configuration Program ( VCP ) Software Download Information
KC-698
May 24, 2022
060000 ENGINE AND ENGINE COOLING
Mack Chassis - Diesel Exhaust Fluid ( DEF ) System Cleaning/Flush After DEF Pump Failure Or System Contamination
KC-686
May 20, 2022
180000 VEHICLE SPEED CONTROL
(Back Office Only) Mack Chassis - Cruise Control Inoperative After Disabling The Electronic Stability Program (ESP)
KC-686
May 20, 2022
251000 ELECTRONIC STABILITY CONTROL:AUTOMATIC (ASC)
(Back Office Only) Mack Chassis - Cruise Control Inoperative After Disabling The Electronic Stability Program (ESP)
KC-663
May 18, 2022
060000 ENGINE AND ENGINE COOLING
Emcon (Spark Assist) Engine Aftertreatment System Troubleshooting Check Sheet - US07 Emissions
KC-653
May 17, 2022
060000 ENGINE AND ENGINE COOLING
Low Oil Pressure Diagnostic Process For 11 Liter Engines
KC-648
May 17, 2022
980000 UNKNOWN OR OTHER
Mack - PTO Pump Speed Calculator
KC-648
May 17, 2022
100000 POWER TRAIN
Mack - PTO Pump Speed Calculator
KC-2169
May 16, 2022
110000 ELECTRICAL SYSTEM
Low Voltage Disconnect (LVD), Function Description
KC-2170
May 16, 2022
020000 SUSPENSION
Electronically Controlled Suspension (ECS) Losing Air Pressure
KC-2172
May 16, 2022
110000 ELECTRICAL SYSTEM
No Start Condition After Over The Air Programing - VECU5 No Start "Safe State"
KC-2172
May 16, 2022
980000 UNKNOWN OR OTHER
No Start Condition After Over The Air Programing - VECU5 No Start "Safe State"
KC-2161
May 13, 2022
060000 ENGINE AND ENGINE COOLING
DEF Pump Cycling periodically Hours After Key Off
KC-627
May 9, 2022
350000 EQUIPMENT
Premium Tech Tool ( PTT ) Training Materials And Support Tools
KC-626
May 9, 2022
100000 POWER TRAIN
Mack Chassis - Vehicles Equipped With An Automated Manual Transmission Model F ( AMT-F, mDrive ), Premium Tech Tool ( PTT ) Gearbox Calibration Failure; Gearbox Calibration Operation Stops And Fails At 33% When Run With Transmission Removed
MACK U - All Years Overview
Complete safety history for the MACK U across all model years (1967, 1992).
57
Total Recalls
0
Total Complaints
0
Investigations
0
Reported Crashes
0
Reported Fires
0
Reported Deaths
MACK U - Year by Year
Compare recalls and complaints across model years. Click any year to see full details.