As yet another UM Ph.D.,
1. What class is this? What type of school? That certainly changes the "chain of command", etc. It also changes whether you have any chance of anyone actually caring about teaching.
2. Dept. chairs & deans certainly can (and sometimes do) lean on younger profs.
3. Saying something like
Quote:
+1 for tell the Dean but word it more of a 'I'm concerned about my grade due to different lecturers, no flow, etc, etc' rather than 'this professor sucks cuz' he's never here, etc, etc'
will get you exactly nowhere. If people pride themselves on anything related to teaching, it's the chance that you might understand the material when you're done with the class, not the chance that you might get a good grade. If, for some reason, they care about the grade distribution, they'll just curve it. So, if you're having trouble learning due to the structure of the course, that's one thing. If you're having trouble getting the grade you think you deserve it, that's another thing.
That said, I'd talk to the prof ASAP. Then the chair. Then the dean if you think it'll do any good.
Talking to anyone higher up before you talk to the prof just isn't likely to work out well for you.