I believe this was a TV movie from the 70’s. It involved a van carrying a pallet of gold bars. The van struggled with the weight. I think there was a scene where the van was going up hill and the gold was sliding towards the back doors of the van during the getaway. I don’t believe they lost the cargo though.
The Italian Job (1969)?
No, but looks like a good movie. The one I’m thinking of took place in the US.
the only heist movie i can think of that involves gold bars is “Oceans 11”
“The Alpha Caper” (1973 TV movie)?
https://www.imdb.com/title/tt0069693/?ref_=rvi_tt
This may be it…wish I could see it to be sure. Can’t find it anywhere online.