Can I send too many letters of recommendation?

Sending additional recommendation letters on top of the three (or four now?) that you already submitted is probably not a good idea. The University of Chicago admissions site states that you must have "two recommendations from teachers who have taught you in an academic subject." You already have the recommendations from your English and Math teachers, so you should leave it at that.

Additional recommendation letters might make them think you're fixated on quantity over quality and didn't take time in the first place to narrow down your choices to the two best teachers for the job. The only reason you might consider sending another letter is if it serves to highlight an impressive achievement that wasn't evident on your original application.

Here's another quote from the University of Chicago site that backs up my point pretty explicitly:

"You may submit one additional letter of recommendation. The writer should know you personally or have mentored you closely in some capacity; this could include a coach, religious leader, group adviser, employer, etc."

Basically, forget about the other teacher recommendations - they won't add anything to your application, and they might make you seem careless about following the requirements set up by the admissions department.