We were in a small conference room at Oshkosh Corp.'s service center along U.S. 41 on the namesake Wisconsin city’s southwest side, talking about the company’s S-Series front-discharge mixer truck, which I was test-driving for the September issue of HDT.

I asked my hosts when Oshkosh first offered this type of vehicle. They were all relatively young, so the product has been in the lineup all the time they’ve been with the company.

“We’ll have to ask Clarence,” said Katie Hoxtell, a marketing and communications manager.

Who’s Clarence? I asked.

“Clarence Jungwirth,” she answered. “He started working at Oshkosh in 1945.”

What – 1945? That’s almost 70 years ago, I said.

“Yes. He’s in his 90s,” she said. “Would you want me to bring him in?”

By all means! And in a few minutes, in walked a slight but spry gentleman wearing a big smile. We shook hands and exchanged hellos, and he explained that he will be 95 this October. He signed on with Oshkosh after leaving the U.S. Army at the end of World War II, and still works a few hours a day helping customers with parts queries and other details, like answering my question about the S-Series’ origin.

“It was in 1986 or ’87, just about the time I retired, when we brought it out,” Jungwirth said, adding that his retirement didn’t last long.

Then he launched into the story of the front-discharge mixer’s invention by a concrete producer in Salt Lake City in the 1960s and its manufacture there, in Indiana, Texas, and back in Indiana, where many are still built today (though by competitors of Oshkosh). “When the patent ran out on it, we were able to get into it.”

That story comprises a chapter in “A History of the Oshkosh Truck Corp.,” a thick, photocopied, spiral-bound book Jungwirth wrote some time ago. It’s one of scores of books and articles he’s authored about Oshkosh -- the company and the city.

Another book is a lengthy account of his time in Wisconsin’s 32^nd Infantry Division, an Army National Guard unit called up for service in the Pacific during the big war. He’s an amateur historian as well as an expert on the many types of civilian and military trucks and trailers that Oshkosh has built since its founding in 1917 and its extensive growth since.

Junwirth is a treasure, and it was a pleasure meeting him on the way to the cab of that S-Series mixer chassis.