I had a recent problem with my main dining room hydraulic slide where it started making a pounding noise when going in along with the slide going in with great difficulty. A close inspection of the toothed rail's pass through the trailer frame showed that the welds for the supporting rollers that support the rack rail away from the frame cutout hole were broken in 2 places, and the toothed rail on the slide was rubbing and bouncing on the lower lip of the frame slide rail cutout. I figured out a way to place a 2 x 4 stud under the roller itself lifted up by a bottle jack on the ground to keep the rail's teeth from rubbing on the frame hole during slide-in movement. Luckily I had a brother Knights of Columbus RVer who is an expert welder come to my space 40 miles away from where he was staying with a welding generator the local church had for maintenance of its steel gates and handrails all over the church property. He welded up the broken places in the rail roller support attachments to the frame while I had the slide jacked up into proper position as described before. The slide now works correctly without physical support assistance.
I thought about the problem, trying to analyze what caused the welds to fail (short of poor quality welds). My analysis is that the roller support attachment welds are under minimal stress when the slides are in. When the slides are out, and I go to climb up on the roof for rooftop maintenance (this slide top is my easiest, lowest roof access) these welds are under maximum stress. Therefore, I have started doing this 2 x 4 stud / hydraulic bottle jack additional support under this slide rack upon space arrival after extending the slides, although the support welds have been repaired and no additional support is needed when retracting the slides.