Yes, as many above have said WD-40 is recommended by the manufacturer and NOT grease. I called CMC to get a torque figure for the bolts since I could spin my washers with my fingers and to my surprise they said that is how it is supposed to be. The nuts on the inside are jam nuts and are not supposed to be used to crank down the outer washers.
Also this is probably overkill, but I do not adjust the jackplate when the boat is in gear. If I want to go higher on the plate after a top end run I will slow down, put the motor in neutral, bump it up and then see how it runs. Certainly this puts less stress on the hydraulic ram. This degree of caution may not be needed, but it is how the previous owner of my boat told me to operate the plate. In fact, he installed a dash switch to raise and lower the plate rather than a second blinker switch. My boat is a 2003 model year and operating it this way it has never had any problems with a leaking actuator.