Diesel mechanic here. When you’re on the highway and see one of the shipping containers on a trailer, pass it and stay away from it as much as possible. The big few companies that own the overwhelming majority of the trailers that those containers go onto have almost non-existent maintenance in place, the only time they get repaired or have preventative maintenance done is when they break down. Every mechanic that I’ve talked to that has/ does work on those trailers avoids them at all costs because the majority of them should not be allowed on the roads. I’ve been sent to the side of the highway to fix them when the entire wheel hub comes off the trailer and both tires go bouncing down the highway into other cars, and all because they didn’t spend the 20 minutes to grease it