Pull the slide all the way out. Now with two people (or a jack) lift the front edge of the slide several inches - it is not fastened down. With the slide raised you can peek beneath it and make sure things are correct. In my 2002 2720SL, there were four rollers under the slide. I added another in the center. In my 2006 2720 SL, there are five rollers. Make sure that all are there, and none are broken or badly out of round.
Some info here
http://www.trailmanorowners.com/foru...read.php?t=340
The outer two rollers ride on an aluminum track. The rollers tends to shed pieces of plastic, which then adhere to the track and form dams. Cleaning the track helped mine a lot.
Finally, if you ride with a lot of stuff on the floor of the slideout and the couch itself (as we do), the heavy slideout will tend to fight you as you pull it. If you can get into the TM and remove some of the heavy stuff before pulling the slider out, it will also help.
Bill