I had a terrible squeal on my first travel trailer slide-out and on my 5th Wheel slide-outs when I first purchased it. All the usual things were attempted. Spraying the bars and any moving parts under the slide-outs themselves with slide out lube etc. It wasn't until the coroplast under the trailer was opened up so those areas near the motors could be spray lubed did it quiet down. I didn't like cutting open the coroplast but it had to be done. I re-sealed it with some special tape the RV dealers use on the coroplast. I hope this helps.