Product review (3 stars): Easy to Install, Inexpensive, and Screeching Door Sounds are Free
Just installed.  The reviews are all spot on. It is an extremely easy fix for a homeowner. You get a complete kit and can replace all the parts on both sides, just the defective part, or any combination. All at a very economical price and delivered promptly. The repair can be done within an hour, less if you review an online video first. So I understand the high ratings. While our door now functions properly (it does not come crashing down when you open it) it makes the awful screeching/creaking sound others have mentioned. Since the plastic piece attached to the string is what broke, I was not able to reuse the existing cord as one reviewer had. And, I followed the advice of another and used WD40 and grease, but to no avail. I tried mixing new and old parts. I even tried using one of the other holes - to increase and decrease tension (the original was set to the middle hole). I am not sure if the springs should also be replaced but I am either buying replacement springs or going to buy the part directly from the Sears Kenmore site.

12/28/15 Follow up: Creaking sound still exists but not nearly as much. Door functions nicely otherwise. Upgrading from 2 stars to 3.