I've included a great link with all the information you'll need to attempt a repair.
Of special interest would be Post #9, and the accompanying link, as it shows and explains how to get the section removed allowing you to access the track area.
Best of Luck!
John & Maria - Chester (furry kid)
2017 Cornerstone 45B - FMCA-#489135
2012 Scion XB - Pushing hard