I bet I know who was behind this...
hahahaha! That's the first thing I thought about!
Probably just sand in a decoy truck.
Rest of story: They just ran out of gas. The new inexperienced guard put the gas through the air vent rather than into the gas tank.
The other guard kind of blew it too when he accidentally told the waitress at their last stop he "had a gold" rather than he "had a cold". Cold, not gold!
"Down with the Gold Standard"
Wonder if Laura Lee Hobbs knows about this?
Sounds like Juanita spilled the beans--and I don't mean the ones at the diner where all the truckers stop.
It's hard for Barney to prevent other crimes in Mayberry when he has to spend so much time doing "trouble checks" there. Otherwise, he might have been more in the loop on the gold shipment.
I find it strange that the crooks just happened to be in the area when the truck broke down and with a truck large enough to haul off the gold bricks. Inside job for sure.