Todd
ScottG is correct, make sure the back wall is supposed to be glued. My Outback was loose as could be and I never noticed it until we traded it in and I was washing it to tow it in for trade-in. I just told the salesman on drop off expecting a change of agreed trade in value and was sure we would take a 2-3000 dollar hit.
The salesman told me upon inspection they appreciated our honesty but not to worry because they were never glued back there on the Outback, he said a lot of trailers were like that.
So check and make sure it is supposed to be glued/bonded back there.
Keith