can reccomend a product called "LUCAS POWER STEERING FLUID STOP LEAK" - its widely recomended on 4x4 forums where steering boxes are renowned for leaking fluid due to design,,,mine included,,, followed instructions and leak stopped instantly,read up about it yourself but a lot of other products make similar claims but the one by "lucas" is much vaunted and did work on mine ----- this applies if you have a leak on your power steering system which if run dry will give heavy steering or gnotchy bits - obviously steering is quite important so get it checked by a mechanic