Thanks for the feedback, guys. If the manual says not to lube the slides, I won't. No problems with them, just thinking "Preventative Maintennance". I have a Reese 16K hitch and I think either of the above recommended products will be good for it. Just didn't want to stumble onto a bad product, so I will look for these.
2016 Chevy LTZ - Duramax/Allison
2008 Eagle 30.5BHS