M1031-
The gen set works great as long as you make sure you ground it right. Follow the directions for using the PTO! Make sure it's fully engaged. The fun part is running air tools from the compressor, like air powered chain saws.
I was in the middle of requesting permission to modify the layout in the truck, product improvement as it were. My guys kept throwing heavy tool boxes and bags of shovels (carpenters/masons) in the back trying to damage the compressor. I would try to move it forward to the bulkhead and screen off the cargo area. Not sure if it would work, never got to the engineering stage.
And, not to be a real d***head, but I can't help myself sometimes. The box is actually called "SHOP EQUIPMENT CONTACT MAINTENANCE TRUCK MOUNTED" (secmtm for short). Marlboro Volunteers in Ohio has one on a Dodge chassis and another they use as a kitchen trailer. The M1031 is the Chevy cab/chassis, or at least it was when my 1st Guard unit got theiirs delivered about 1990.