I haven't seen this problem posted before, but now that I have, someone will probably have the problem(as said by Mike and Pat, I believe. On the 39K galley slide, under the large pull out drawer at the end of the sink(next to the J-sofa) is a 6-7" roller that I believe helps support the slide on the floor when it is retracted. I noticed mine was gouging the floor when retracted so I decided to investigate. I pulled the drawer out completely and there was a piece of luan paneling on the framing bottom that was poking up on one side.
I cut out that piece of luan and found the roller at a tilt to one side. It is screwed into the aluminum floor support framing from the BOTTOM of the framing with an ear on each end. It is totally impossible to remove w/o removing the slide in my opinion. I had one of the ears break off which kiltered the roller at an odd angle and when the slide was in, the end of the roller assembly was hitting my floor.
I ended up drilling and installing some self tapping #12x1" ss screws in the bracket assembly to the aluminum framing sides which I think will solve the problem. I have a pic on my phone but I don't know how to download it to this site or even if it is possible. If anyone needs a pic, you can pm me with your email address and I can sent it to you that way.
So anyway, you 39K owners, if you notice a gouge in your vinyl floor tile just ahead of the drawer when the slide is out, that is probably the problem. I apologize for not being able to describe it in more detail, it is complicated.