Slides with cables

We have 3 cable slides in our Cougar. We have a lot of problems with our kitchen slide. It seems to be too heavy even unloaded. We have lost the motor and striped the gears in the transmission. Part of the problem seems to be that they used a solid Teflon bar for the slide to sit on; the other 2 slides have rollers under them and have no problem. I routinely clean off the bottom of the slide and use ptfe or other drylube on it to help it slide easier. We also have to assist the motor in extending or retracting the slide by pushing on the slide.