I have the same year Providence and have had the same problem. No, the motor is not bad and does not need to be replaced. When you can, crawl under the slide and find the motor. On the gear end, there is a rubber boot, covering the brake. Squeeze the the rubber, you can feel the brake, as a toggle. Push it which ever way it will go and the brake should then engage. I've done that a couple of times and the slide will not ease out while traveling. I don't know why the brake comes unlocked but it does. I haven't had anymore trouble for several years now.
Roland & Jerri, with Maggie & Mollie, our Pups; '05 Fleetwood Providence, 39' DP; '08 Saturn. "The difference between genius and stupidity is genius has it's limits" (Einstein)