If you put the transmission in park and accelerate, does it make the humming noise? The question becomes where is it actually humming from. You can always check the fluid level and top off as necessary following the instructions in your owner manual. You might have a CVT in which case probably isn't good news based on reports from other Saturn CVT owners....
Search Saturn VUE Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Saturn VUE Experts