I have no idea how your gasket is attached but the one on my frig came loose and upon examining it all that had to be done to reattach it was to take a screwdriver and push it back into a slot in the door. You might see if yours will pull loose from the corner and if it just fits in a slot or better yet call the repairman and ask them how it is attached.

You can get advice on how to do repairs at repairclinic.com - they also sell parts.

I replaced one on a 36 inch Sub Zero and it was fairly difficult. I think it will depend on the make of the fridge. But if you're handy, give it a shot.

The thing to remember is that taking off the old and putting on the new one is all one job. You can't split it into two jobs.

I replaced on e about 10 years ago on a GE top freezer model. It was tedious, but not difficult. It took about 2 hours, but that was including the removal of the old one, reading the directions and really taking my time to be sure the new one was installed properly. You can always attempt it and if you are unsuccessful, call the repair person. It is easier if the doors are empty and the fridge is at least partially empty as it takes so long. G