Moderately difficult. This fan requires an exact match of two opposing "stems" to the corresponding holes in two rubber grommets. The stem fit of the stems to the grommets is critical as this fit "grips" the fan motor in place, preventing vibration and rotation around the stems. Because the new fan motor was .160" thinner than the original, it create a very sloppy fit. I was able to make up the difference with one (1) steelwasher on each stem. However, the fan motor rotated about 30 degrees around the stems when installed. To prevent the rotation, I shimmed the frame of the motor against it's mounting frame. It works, but I need to go back in and make a better mounting method. If Sears could provide two (2) .100" rubber washers to make up for the lose fit of the stems, the installation would be snap.
Part of the problem is I have a 30 year old Amana TC20N Refrigerator. The replacement part is a Whirlpool. Close, but not close enough. It took an hour to swap out the fans.