Bedroom Slide Hanging up going out???

[Jack in Alaska]

2004 MS, 33', RE3..........my bedroom slide (electric) hangs up when about halfway out. It is catching on the front side (nearest the RV front). A little pushing/wiggling, by me while wife runs the switch, on that side gets it going and then goes all the way out. It retracts fine.
I have looked at all of the surrounding seals and the underside and it all looks just fine. The underside white board is perfect, teflon blocks are in place etc.
What supports the slide itself on the foot end of the bed.?? Are there teflon blocks there also or does it just slide on the carpeting??
The MS is in storage in Wash. state, I am in Alaska so I do not have the opportunity to mess with it. I thought about sliding apiece of 1/4" teflon board under that side to provide a smooth surface to slide on.
We will be together again in mid-Oct. Then on to Az. for the winter.

Any ideas from you MS owners???