Power assist (or the lack of) is really only noticeable/necessary at speeds below 20-30 mph. The slower you are going the harder it's going to be to steer. So for highway/interstate speeds you aren't going to notice a lack of power steering assist. I would recommend taking off your power steering pump belt if your pump hasn't started whining/groaning/complaining yet. If you let the pump get too low on fluid you'll burn it up and have to replace it.
