Originally Posted by BoatDude
I asked a tech the same question. He said to use WD-40 to prevent surface rust on the cylinders. Also the slide mechanism bars and use a silicone grease on the gears and racks.
Your "Tech" may not be as correct as he/she needs to be. WD-40 may not be compatible with the seals or the transmission fluid if it makes it past the seal. WD-40 also has other properties that
could cause damage due to their nature over time.
As for the slideouts I quote from Lippert: "The Lippert Hydraulic Slideout System has been static tested to over 4,000 continuous cycles with out any noticeable wear to rotating or sliding parts. It is recommended that when operating in harsh environments (road salt, ice build up, etc.) the moving parts be kept clean and can be washed with mild soap and water. No grease or lubrication is necessary and in some situations may be detrimental to the environment and long term dependability of the system."
Bottom line is unless your "tech" is smarter than the engineers that made this stuff, one might consider sticking to what the folks that design this stuff recommend.
Of course, if one is going to ignore good counsel and go rogue on the subject, why not use cosmoline?
I don't mean for this response to be short, it's just how I write. I used to consider tonal quality but gave it up when I retired.