Don't get me started on this haha! We have this same problem. We took it to the dealer while still within our warranty period, they stated that it's a known problem, but neither Lippert nor Keystone will fix it. We paid out of pocket to have the hydraulic fluid changed (as that was what was suggested in our research online) but they still make the noise sometimes, just not as bad as before. They do do it during the day and in various weather conditions, but it's harder to notice it since we're not laying right above them during the day like at night. So basically, we're SOL and just have to deal with it.
ETA: forgot to add we also added some dry lubricant to them, but that didn't seem to help.