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.
- NHTSA ID
- 11751707
- Incident
- Mar 16, 2026