ok, dont go and soak anything in wd40. you could end up damaging connectors and or wires. if you are going to use anything make sure its subber safe, as you could end up spraying other things aside from the u-joint. plus wd40 isnt a lubricant... its a water displacer - hence the WD
if you're steering, and dont hear grinding noise, or have any physical binding, or sloppiness - its not your steering shaft or its u-joints bearings
whats probably failing is your electric power steering system.
