Depends on the manufacture. On my Reese Dual Cam, I put grease on the spring bars where they fit into the head assembly. Reese suggests a heavy oil there. I grease the ball, also. I use Vaseline on the spring bars where they ride on the cams. Reese instructions says not to use oil or grease there, but Vaseline is OK. On my last trip, I WD-40d my chains, and that quieted those down, but the links collected too much road grime and dirt. I think I am going to try silicone spray next trip to see how that works.
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263