- The problem
- 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.
- The fix
- 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.
Vehicle safety record
1977 Mack DMM Problems, complaints & recalls
No owner complaints about the 1977 Mack DMM have been filed with NHTSA. It is covered by 5 recalls, the latest in May 1979 for the engine.
NHTSA data checked
FFar more problems than a typical DMM year, for its age
- Complaints
- 0
- Recalls
- 5
- Crashes
- 0
- Fires
- 0
- Injuries
- 0
- Deaths
- 0
1977 Mack DMM recalls 5
Recall repairs are free. Your dealer fixes them whether or not you bought the car there - check your VIN at nhtsa.gov/recalls to see if yours is done. What to do
- The problem
- 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".
- The fix
- 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.
- The problem
- 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.
- The fix
- The dealer will inspect and, if necessary, install cross steering arms of improved design and greater strength.
- The problem
- 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.
- The fix
- Dealer will inspect and, if necessary, replace seat belt assemblies without charge to owner.
- The problem
- 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.
- The fix
- Dealer will replace the original fan with a steel fixed blade fan, free of charge.
What owners say
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No complaints about the 1977 Mack DMM yet
No owner has filed a complaint about this vehicle with NHTSA. If yours has a problem, share it here and report it to NHTSA.
Mack DMM: every year compared
All DMM yearsQuestions about the 1977 Mack DMM
Does the 1977 Mack DMM have any recalls?
Yes - NHTSA lists 5 recalls for the 1977 Mack DMM: engine (May 1979); interconnecting assembly(wiring) (October 1978); arm (August 1978); anchorage (October 1977) and more. Recall repairs are free at any authorized dealer. Enter your VIN at nhtsa.gov/recalls to see whether yours has been fixed.
How many complaints has the 1977 Mack DMM had?
None have been filed with NHTSA so far.
Is the 1977 Mack DMM a reliable vehicle?
Its Safety Index is 8 out of 100 (grade F: far more problems than a typical Mack DMM year, for its age). The index weighs complaints, crashes, fires, injuries, deaths and recalls against how long the vehicle has been on the road, compared with the same model's other years. It is not a measure of every repair - read the complaints and owner experiences, and have any used vehicle inspected before you buy.
What should I do if my 1977 Mack DMM has a problem?
If it is a safety problem, stop driving it if it is unsafe and contact your dealer. Report it to NHTSA at nhtsa.gov/report-a-safety-problem - enough reports start investigations and recalls - and share your experience here so other owners know what to look for.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) complaints and recalls, checked . Complaints are owners' own reports and are not verified. How we use the data