2025 Mack Granite (gr) Problems
Owner-reported complaints filed with NHTSA, grouped by component
Data refreshed
What this page shows
Everything below is an owner-reported complaint submitted to NHTSA about the 2025 Mack Granite (gr), grouped by the component NHTSA recorded on the report. These are not confirmed defects, and they are not recalls. NHTSA does not verify most reports before publishing them, and a category with more reports in it is not evidence that a part is defective.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Reports by component
Ranked by how many owner reports name each component category
- Electrical133.3%
- Engine133.3%
- Powertrain (other)133.3%
Percentages are of component mentions. A single complaint can name more than one component, so these do not sum to the total complaint count.
Each component in detail
What the reports in each category say, in the owners' own words
Electrical
Reports naming the electrical system — wiring, battery, charging, control modules, infotainment and electrical accessories.
From owner reports, verbatim
Background and Contracted Scope At the recommendation of Mountain West Service Manager Kendall Weaver, I contracted with Mountain West to install an engine-mounted PTO (Power Take-Off) hydraulic pump on Truck #37 for use in a side dump trailer application. Kendall represented that the engine-mounted system would be more powerful and better suited to the truck. A side dump trailer requires bidirectional hydraulic flow — controlled pressure in both directions to operate the dump body. The pump specified and contracted for was Volvo part #20392944, a premium piston-type hydraulic pump with an integrated clutch, allowing the pump to disengage from the engine when not in use. Day 1 of the installation — Mountain West Service Advisor Michael Korgenski emailed: "We are not able to install the pump because without the bypass valve the pump will continue to run dry and burn up. Body builder will need to install and plumb the pump and valve." The Mack dealer intentionally substituted the pump with an incorrect pump that creates constant hydraulic pressure. This incorrect pump has caused hydraulic lines to burst three times on the highway, dumping approximately 20 gallons of hydraulic fluid on the highway, the truck then begins smoking and overheating risking fire. The dealer instead of fixing the truck correctly insists on using the wrong spec parts and wants to build a work around, that they stated may or may not work.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Engine
Reports naming the engine itself — including stalling, misfires, oil consumption, cooling and internal engine components.
From owner reports, verbatim
Background and Contracted Scope At the recommendation of Mountain West Service Manager Kendall Weaver, I contracted with Mountain West to install an engine-mounted PTO (Power Take-Off) hydraulic pump on Truck #37 for use in a side dump trailer application. Kendall represented that the engine-mounted system would be more powerful and better suited to the truck. A side dump trailer requires bidirectional hydraulic flow — controlled pressure in both directions to operate the dump body. The pump specified and contracted for was Volvo part #20392944, a premium piston-type hydraulic pump with an integrated clutch, allowing the pump to disengage from the engine when not in use. Day 1 of the installation — Mountain West Service Advisor Michael Korgenski emailed: "We are not able to install the pump because without the bypass valve the pump will continue to run dry and burn up. Body builder will need to install and plumb the pump and valve." The Mack dealer intentionally substituted the pump with an incorrect pump that creates constant hydraulic pressure. This incorrect pump has caused hydraulic lines to burst three times on the highway, dumping approximately 20 gallons of hydraulic fluid on the highway, the truck then begins smoking and overheating risking fire. The dealer instead of fixing the truck correctly insists on using the wrong spec parts and wants to build a work around, that they stated may or may not work.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Powertrain (other)
Powertrain reports that are not specifically the engine or transmission — driveshafts, axles, transfer cases and differentials.
From owner reports, verbatim
Background and Contracted Scope At the recommendation of Mountain West Service Manager Kendall Weaver, I contracted with Mountain West to install an engine-mounted PTO (Power Take-Off) hydraulic pump on Truck #37 for use in a side dump trailer application. Kendall represented that the engine-mounted system would be more powerful and better suited to the truck. A side dump trailer requires bidirectional hydraulic flow — controlled pressure in both directions to operate the dump body. The pump specified and contracted for was Volvo part #20392944, a premium piston-type hydraulic pump with an integrated clutch, allowing the pump to disengage from the engine when not in use. Day 1 of the installation — Mountain West Service Advisor Michael Korgenski emailed: "We are not able to install the pump because without the bypass valve the pump will continue to run dry and burn up. Body builder will need to install and plumb the pump and valve." The Mack dealer intentionally substituted the pump with an incorrect pump that creates constant hydraulic pressure. This incorrect pump has caused hydraulic lines to burst three times on the highway, dumping approximately 20 gallons of hydraulic fluid on the highway, the truck then begins smoking and overheating risking fire. The dealer instead of fixing the truck correctly insists on using the wrong spec parts and wants to build a work around, that they stated may or may not work.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Elsewhere on this vehicle
Data sources
- NHTSA Office of Defects Investigation — owner-reported complaints and the components recorded on them
Data on this page last refreshed .