Check a vehicle VIN check Latest recalls Latest complaints Common problems Rankings Compare vehicles Recall roundups All makes Guides Share your experience
Theme

Fuel system

Mack MD Fuel System problems by year

1 complaints filed with NHTSA about the Mack MD's fuel system. Fuel pumps, leaks, injectors, fuel smells, gauges and stalling caused by fuel delivery.

Fuel System complaints by model year

YearFuel System complaintsCrashesInjuriesRecalls
20231000

Latest MD fuel system complaints

2023 Mack MDTransmission & drivetrainEngine & coolingFuel system

COMPONENTS THAT FAILED: Multiple systems failed in a connected chain. (1) The DPF aftertreatment differential pressure sensor - a CONFIRMED manufacturing defect per Cummins recall T7186/T7187 (Jan 2026). (2) The Allison automatic transmission - catastrophic internal failure: torque converter destroyed, flexplate warped and cracked, metal fragments throughout. (3) The transmission control unit wiring (circuits 143/123) reversed at the factory. The DEF sensor in the same aftertreatment system also failed back in Dec...

Read the full complaint

2023, 14 months before the DPF symptoms - proving a system-wide defect. All failed components and repair invoices are available for inspection upon request. SAFETY RISK: After the dealer declared repairs complete, the truck was driven under 10 miles when the engine entered SEVERE DERATE (limp) mode WITHOUT WARNING, with four alerts firing at once including aftertreatment and transmission failures. Sudden, drastic power loss on a heavy commercial truck in live traffic is extremely dangerous - it can leave the vehicle unable to maintain highway speed, risking a collision with surrounding vehicles. The dealer released the truck in this hazardous state with no warning. CONFIRMED BY MULTIPLE SHOPS: Yes. The problem was reproduced and confirmed repeatedly - by the authorized dealer, by an independent transmission shop, and at final repair. The fault returned within 30 minutes on one visit and within 10 miles on another. INSPECTED BY: The authorized dealer and an independent service center inspected the vehicle and failed components. Documentation is available. WARNING SIGNS: Yes. Warning lamps appeared from the very first visit in Feb 2025 - transmission code P071A and high soot codes 1981/1922. They persisted for NINE MONTHS without proper repair, until the transmission catastrophically failed in Nov 2025. The vehicle was out of service over 45 days.

Filed Incident Power train · Engine · Fuel / propulsion systemNHTSA 11744905

Source: U.S. National Highway Traffic Safety Administration (NHTSA) complaints and recalls, checked daily. Complaints are owners' own reports and are not verified. How we use the data

Owners helping owners

Know before you drive.

Every experience you share - good or bad - shows on that vehicle's page and helps the next owner and buyer. Two minutes, anonymous.

Share your experience