Leaked audio reveals that Trump didn't know semi-trucks run on diesel - yet the industry is one of Trump's most ardent supporters

• Truck drivers were key for President Donald Trump's 2016 election.
• Executives from the $800 billion industry have met with the leader several times during his tenure to help him push his healthcare and tax reforms.
• Still, according to a leaked audio of a 2018 dinner published by The New York Times, Trump's knowledge of the trucking industry shows surprising gaps.
• Trump did not know trucks run on diesel. He was not aware of two critical issues that are roiling the trucking industry: the truck driver shortage and the electronic logging mandate.
• Visit Business Insider's homepage for more stories.

A leaked audio recording of a 2018 dinner with President Donald Trump and key donors has provided new insight into the president's dealings with Ukraine, as well as his relationship with businessmen Lev Parnas and Igor Fruman, two crucial characters in Trump's impeachment scandal.

The April 30, 2018 dinner revealed something else of the president: that his knowledge of trucking is less than comprehensive.

For a little more than 10 minutes of the 83-minute audio clip, Trump talked with the major donors attending the dinner about the $800 billion industry. The New York Times identified one executive as Chicago-based billionaire Barry Zekelman, who owns North America's largest maker of steel tubes.

Another attendee was Wayne Hoovestol, according to the Times. Hoovestol owns several trucking companies in the Midwest, including Eagle Express Lines, which grossed more than $450 million in 2018. According to Transport Topics, Eagle Express is the No. 2 largest carrier of US Postal Service mail - hauling USPS parcels through long-haul trucking.

Hoovestol did not immediately respond to a Business Insider request for comment. A media representative from the American Trucking Association told Business Insider that he was not aware of whether any members of the organization attended the dinner.

The White House did not immediately respond to a request for comment.

'Why can't you? Just not as strong?'

After a short conversation on Tesla and electric passenger trucks, a voice that identifies himself as a trucking executive who has worked with the USPS begins talking about the challenges with fueling semi-trucks. According to the leaked audio, here's how the conversation followed:

Trump: What do you mean trucks? What do you do? Where did you say you work at?

Trucking executive: Our main thing we do, we haul mail for the postal service.

Trump: So you know the difference. Right? You have every kind. Is there anything like gasoline?

Trucking executive: Nope. Well, diesel is trucking.

Trump: How is diesel compared to regular gasoline?

Trucking executive: Diesel in a semi - you can't run gasoline in a semi.

Unidentified voice: Right, big tractors.

Trump: But, why can't you? Just not as strong?

Trucking executive: It doesn't have the BTUs that diesel has.

Following that conversation, other voices talked with Trump about other major issues in the industry, including the truck driver shortage and the implementation of electronic logging devices.

Trump also appeared unaware that truck drivers have safety regulations that prevent them from driving more than 11 hours a day. Some 4,678 people died in accidents involving large trucks in 2018, including 885 truck drivers.

"You mean they can only drive so much?" Trump said in the recording. "Like a pilot? I didn't know that."

Truckers and their employees have supported and met with Trump multiple times

Trucking executives and industry experts who listened to the tape shared with Business Insider said that they were astonished by Trump's ignorance.

They said they were doubtful that the president would not have been told previously about many of the basic points covered in the ten-minute conversation. The gaps in Trump's knowledge - including his ignorance that 18-wheelers run on diesel, not gasoline - contrasts with his ongoing interactions with the trucking industry.

The April 2018 dinner was not the first, or last, time Trump interacted with the trucking industry.

A year before the Washington dinner at the Trump International Hotel, Trump welcomed truck drivers and ATA representatives to the White House to discuss healthcare. Trump even climbed into a big rig parked on the White House's South Lawn and tooted the horn, as transportation executives gathered around the truck laughed.

Several weeks before the dinner, representatives from the ATA returned to the White House to champion Trump's 2018 corporate tax cuts.

"Our industry could not ask for better representatives than these to talk about the benefits of the President's tax reform package," said ATA President and CEO Chris Spear.

Read more: Truckers voted for Trump in droves. Now they say his trade war is 'killing' their ability to make a living.

Beyond Trump's repeated interaction with trucking executives, America's 1.8 million truck drivers were key supporters of Trump in 2016, according to an Overdrive magazine survey from 2016. About 75% said they planned to vote for Trump, up from 66% who supported Sen. Mitt Romney, the Republican presidential nominee in 2012.

The industry has lent significant monetary support, too. The trucking industry contributed just over $9 million to the 2016 election, 81% of which went to Republican candidates. Trump's 2016 campaign received $331,000 of that, according to Federal Election Commissions documents published by The Center for Responsive Politics.