Tom, not sure if your slide is the same as my 08 Endeavor but on my large drivers side slide they used plastic wheels under the slide which will crack and break. These wheels are hard to see if you don't know where to look. The guys to call are Elite Repair and Remodel in Harrisburg Oregon 541-995-4767. They all worked for Monaco for years and are very knowledgeable. They should be able to point you in the right direction.
Brian, Loretta & Daisy (Golden Retriever)
2008 Holiday Rambler Endeavor 40 PDQ , ISL 400
2014 Ford Explorer toad