Not only the humor but in all aspects The British tend not to cowtow to interests or worry about "political correctness" BS.
I did a quick dig and found. "Jay Leno who originally turned down offers to host the show, expressed concern over whether or not a show like Top Gear could be successful in America. In a column published by The Sunday Times Leno expresses concern that an American version could lack the critical reviews the British version is known for. The British show is produced for the BBC with public funds while the American show will air on commercial television. Leno believes that the show may have to worry about offending current and potential sponsors by giving their products poor reviews, leading to a compromise in the journalistic integrity and freedom of the original show."
New crew, all American. The show wasn't bad. But not as funny. I like the dry British humor.
All humor aside, it wasn't bad. Better than the first British version in season 1. I think with a bit more feedback, they can make it better over time. You have to consider that this will take some polishing.