I wouldn't put RPM on anything that you want to go where you want it to go :D
Another thing that I don't like is that the screw holes strip easily, take off the shocks a couple of times and you need a new set of arms.
Just try out a couple of oils, it's like 5$ a bottle and 15 minutes of work to do it. We really can't tell you for a truck we don't know and surface we don't know... Maybe you need to change springs or something else entirely? Do you have someone with the same platform to copy their setup?
You...