Back in the early 80's I had a job driving vehicles out of the AM General plant in South Bend, Indiana to railroad spurs around northern Indiana for transport to locations unknown.

There were new United States Post Office vans, new military HUMVEEs or hummers, as we liked to call them and 5 ton trucks that were being refurbished under the E.S.P.
They'd get the 5 tons in from all over the world, bring them to South Bend, strip them down, and rebuild them from the frame up, making them "good as new". They were all diesel. They all had automatic transmissions. They all had power steering. And they all had 6 wheel drive.
As I recall, we would hop on, pull the duct tape off the exhaust stack, pull the duct tape and plastic off the dash, then flip on the glow plugs until an indicator light went on. Then we'd fire up the engine and wait for the air pressure to build up. When another indicator popped on and the air pressure was up, we could release the brakes.
Now, the AM General plant has a lot of sandy, sloping parking areas that are pretty steep. They also have a HUGE test track on the plant grounds that is both on and off road. If we were lucky enough, our batches of 5 tons for the day would be out in the sticks, on the far side of the parking area near the test track. We'd flip the lever to engage the front axle, then sneak out the back of the parking area and drive through the test track. :laughing:
I was very impressed at how easily those huge trucks could go through mud and steep sand, as well as the slopes on the paved sections of the track. They were quite impressive.
They came in many configurations:
Troop carrier with benches in the back.
Dump truck.
Wrecker truck.
Crane truck.
Flat bed truck.
And a few others.
After we got chased out of the test track areas by security, we would drive to rail spurs around the area and load them on flatbed rail cars for shipment. We would travel in groups of 6 to a team. One time we were driving down a road and were supposed to turn right down a side street near the rail spur. I was near the back of the line. A red Cadillac passed me on the right. Apparently he was tired of following us. It was not a two lane street, but he squeezed past me, and a few other trucks in front of me. Now, these trucks had no rear view mirrors. They were boxed up in a crate in the back for shipment, along with the top of the exhaust stack, the windshield and a tool kit. Well, the Caddy got up next to the front truck just as he made his right turn. The Caddy driver slammed on his brakes, which lowered the front end pretty good, just as the left front corner went under the 5 ton right between the front and rear axles. That truck drove over the hood of the Caddy like a speed bump and just kept going. He thought he hit the curb! :laughing: It flattened the front of the Caddy to the ground! We all laid on the horns to get his attention. I guess we should have laid on them a bit earlier.
Anyhow, the Caddy driver was unhurt, but quite angry. :mur:
So, to sum it up... the 5 ton is a fine tough heavy duty truck that is very easy to drive. We did not have to get CDL licenses to drive them back then, but we did have to get a Chauffeur's license. That was because we used our personal cars to transport the team back and forth between the rail spurs and the AM General plant.

Check into your local state for requirements.
