The problem with WD-40 is that it's not a long term lubricant. Technically, it's not really a lubricant at all, it's a solvent and rust dissolver. What you'll end up doing is washing away the thicker grease and dry out the gears in the long run. It'll seem better right now, but long term you should not use WD-40 to lubricate the assembly.My mirrors doing the same, I'm thinking of spraying WD40 on the mechanism, I'm not taking the mirror apart or anything, I will just spary it around (behind the mirror glass)and soak it!
+1WD-40 strikes me as more of a stopgap measure just because of its low viscosity.
A quick search turned up this bit of helpful, if generic, information: https://www.machinedesign.com/mecha...ubrication-tips-plastic-gears-and-more-part-2
Personally, I would open up the mirror assembly and hit all the appropriate points with some white lithium grease...