Sears review: foul odor from the drain pan

We purchased a Sear Elite French Door Refrigerator/Freezer approx. 2-3 years ago. We started to experience a foul odor coming from the back of the unit. After doing some investigative research on the internet, it seems that the drip pan cannot be removed in order for it to be cleaned. There was a lot of stagnant water that filled the pan and caused it to overflow. How do you resolve this problem? I did chat with a representative from Sears, who told me to check the manual which I did. No were in the manual does it tell you that you can remove it. What kind of product is this? My model number is 795.71033.010.