This one is tricky. Why?
The main poll you can find on this matter is from Pew. However, the issue I have with it is they group their information as such.
High School Diploma or less. Some College. Bachelors. Post Graduate.
My issue here is with the "high school diploma or less" category. They recognize that there is a difference between someone who attended some college, and those who actually graduated; yet they decide to lump together those with some high school experience with those who actually graduated.
Now, using Pews data, it seems like there is a larger raw number of left leaning voters who make up the lowest category, while at the same time they also have the larger raw number of people in the higher categories as well. This, in part, is because as of 2016 left leaning voters make up 4% more of the registered voter base than Republicans. When talking just percentages, there is a higher percentage of republican votes in the lowest category, with a higher percentage of democrats progressively as you go up to the higher categories.
Again though, the issue here is the fact that when I hear "uneducated" voters, I'm not necessarily thinking of "high school educated and less"; I'm tending to think of people who don't even make it out of high school. Your drop outs that either couldn't, or didn't want, to make it through that level of education. And right now I'm just not finding a lot of good information there.
Mind you, this is all talking from the notion of "formal" education.