The vacuum pump is used on the heavy duty turbocharged (L65, VIN F) 6.5L diesel engine to operate the emission control (EGR valve), the cruise control and the heater doors. The diaphragm-type vacuum pump does not require periodic maintenance.
The pump is mounted by a bracket at the left front of the engine. It has a pulley attached that is belt-driven. With the exception of the pulley, the vacuum pump is replaced as an assembly.