I only know two things about that. 1) You can't do it yourself. it requires special tools that not even every shop will have. 2) Depending on what gear you are starting with and what gear you want to end up with, you may have to buy more than just a ring and pinion. There is a thing called a carrier and there are diffrerent ones for different ranges of gears. Sorry i can't be of much help, I am in college too and am new to a lot of this.