The rubber insulation around the door has become brittle and cracked. Is it fixable and, if so, where can I obtain new insulation?
At the Sears parts site I found that the door gasket part number is 8330331652770
You may want to double check this.
Try Googling “8330331652770 gasket” to see if it is available somewhere.
Could also try the part representatives at AppliancePartsPros.
Just because the unit does not come up on their site does not mean that they do not have access to the parts.
I know there are companies out there that do supply different gasket formats.
Perhaps the following will also help.
http://www.applianceaid.com/refrigerator-door-repair.php#gasket