I think we still have people with technical ability. There are several MOS's (Military Occupational Specialty) that I know of, that could readily do this repair. But one of the big changes made by MEP, (Mobile Electric Power), many years ago, was to reduce training time for some MOS's. And to combine some MOS's, as they were very similar. Back in the 70's, my was MOS, 52B, Power Generation Equipment Operator/Mechanic. Start, stop, basic maintenance of all power generation equipment.
The next step up, and 3-4 months more schooling was 52D, Power Generation Equipment Repairer. These were the people who worked in the next level of repair. Direct Support maintenance. The could be assigned to line units, and were often done so. They became responsible for running an entire Power Generation section, normally for units that had larger gen sets. Hospitals, Missile units, Radar units and such things. But most 52D's went to DS maintenance units, and did higher levels of work. This was the guys who did electrical repairs, of almost any part in the gen sets. They also engine replacement, and engine repair, up to major engine rebuild.
MEP decided that there were items, that took to long to repair, that the number of repair parts needed to be stocked would be drastically reduced by not performing these repairs. More Mission Readiness Time, less Maintenance and Supply time. And at the end of the day, this was a wise decision. The overhaul of a diesel engine would take at least a week, if all went well, and that simply never happened. Even if the Technical Supply had the rebuild kit, should you find some other part that needed to be replaced, the supply time stretched out even longer. And a unit needed more tools and test equipment. I had two young studs who could pull out a 30 KW engine in three hours, and have the new engine back in in 4-5 hours, and start a test run. As a commander, what would you want?