We have very large oak trees that tower over our house with the bottom branches simply too high to inspect by hand.  The trees are  infested with something that is shredding healthy leaves and these sticky tiny black balls (like specks of dirt) are falling all over the place.  When they fall on our cars, these balls are hard to wash off with a garden hose and we need to push them off with a rag.  Anyone know what kind of insect could be causing this?

Several types of insects leave behind a black mold type of stuff on the leaves. White flys are the culprit around here. Do you have the black stuff on any other plants in your yard?

No, it was only falling from the trees.  It has stopped now and we spoke to a neighbor who said it could be some kind of caterpillar poop. lol.  He could be right because we now have strings coming down with small green caterpillars dangling from the branches.  We'll probably have to spray for them next year.