Many stories about Donald Trump ascribe his support to "working class" voters. But none of them cite any figures about class differences in support for Trump, for the good reason that almost all commercial surveys stopped asking about occupation sometime in the 1970s. So if you adopt a conventional definition of the working class as people employed in manual occupations, we don't know, and maybe never will know, if working class voters helped Trump to get the Republican nomination. (The American National Election Studies and General Social Survey still ask about occupation, so eventually we'll be able to say something about class and the general election).
Surveys today generally ask about education and family income, and Trump clearly does better among less educated voters. In the ANES Pilot Study, 42% of people without a high school diploma and only 29% of people with a college degree said they favored Trump*. If you control for education--that is, compare people with the same levels of education but different incomes--there's no evidence that income makes any difference.
You could say that the conventional view is right: since people in working-class occupations have less education than people in middle-class occupations, it's reasonable to think (although not certain) that working-class voters are more likely to support Trump. However, speaking of a class difference focuses attention on economics; calling it an educational difference focuses attention on other factors. For example, there's a lot of evidence that education increases support for civil liberties and acceptance of complexity and ambiguity, and those things certainly seem potentially relevant to support for Trump. If we just had information on education, those two interpretations would be about equally credible. But the fact that income doesn't make any clear difference after controlling for education suggests that the non-economic side of education is more important.
The usual account is that working-class voters are turning to Trump out of frustration with a long period of flat incomes. But it's not just the working class that has experienced that--it's a substantial majority of people. Depending on the exact time period and how you measure things, the group that's had a substantial increase in income might be as small as the top 1%, and not bigger than the top 20%. So to the extent that economic frustration matters, it should apply to large parts of the middle class. In fact, there is a hint in the ANES data that support for Trump is lower among people with incomes of more than $100,000, but the sample is too small to be sure about that.
*All figures refer to Republicans and Independents who leaned Republican or didn't lean towards either party.