The problem was most likely the evaporator fan motor but it could have been a bad blade, loose parts or bad motor mounts. Hard to tell without taking everything apart and inspecting. Since fridge was 17 years old I decided to order the entire evaporator fan assembly as shown in the parts diagram including fan blade, motor brackets, motor, motor mounts, screws, etc. Getting to the assembly involved removing the ice maker unit plus the entire rear inside of the freezer section. Parts cost around $300+ but it was worth it because all the brackets, screws. etc. were completely rusted and the rubber motor mounts were shot. Also, it's a nasty, 2-hour job that involved uttering a few four-letter words so I only wanted to have to do it once. It now runs like new!