Our 04 Imperial did something similar. The motor unit has a drive gear on it that broke off two teeth and did a skip when deploying and retracting. When the slide is deployed there is a gear rack on the underside of the slide that is driven by that gear. It was covered under the drive motor mfgrs 2yr warranty. That slide, that has the bed in it, has been removed and repaired under warranty twice when we first go the coach. Later I had to thru-bolt the bed unit to the slide to keep it from binding when in use. After I got those things straightened out it has worked perfectly since.
2004 HR Imperial