Just to confirm, are we talking RR30xx or RR50xx?? Swoop's answer seems to be relevant to RR30xx machine.

If RR50xx, which lift motor is running as soon as you turn on, the front or the rear? If rear then P2 pump contacts maybe welded shut but Access shouldn't allow line contactor to close if they are. If front motor is running as soon as you turn on and are standing on the foot pedals then thats normal (for steering) but if forks are lifting at this point without touching the multifunction handle then either the proportional lift valve is stuck open or it is receiving an erroneous electrical signal.

More info required really, are you standing on the truck or off it when you key on? Is the line contactor closing? Is oil coming out of the breather or the filter housing? Are you sure the return pipe from the steer system to the filter housing isn't split? Is the black filter housing cap fitted correctly as they can be a real pain to get locked down properly and will leak if not? Is the filter clean?