I don't think you would be able to replace yourself. It is not reachable without removing the slide.
When my 2552 was still almost new my seal also came loose. Knowing the PC will pay a local RV dealer to fix a warranty repair, I went to one. They said it was too complicated and they would charge too much that they knew PC would not pay that much.
We set up an appointment with PC, they did the whole job in 5 hours, but it involved disassembling the dinette, removing the refrigerator which is in the 2552 slide. They used a towmotor to remove the slide and installed the new seal not just with adhesive but screwed it to the floor.
Here is the story from an old Blog.
http://khmexico10.blogspot.com/2012/11/rv-factory-repair.html