A full wall slide usually has multiple drive motors and they need to be synchronized so that the slide moves straight. The synch procedure probably depends on the brand of the slide mechanism (Schwintek, Power Gear, etc.). Not a simple process, from what I read.
Here is a video on a Schwintek:
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL