GMC Repair: Power Steering going weird, power steering pump, ps level

Question
I think it might be the p.s. pump??  When I am stopped it is very very hard to turn, when I am driving it is ok...checked ps level its fine.  Could this be the power steering pump on its way out?

thanks

Answer
First thing to check would be to make sure the power steering pulley shaft is not broken, you can do this with a long screwdriver, pry behind the pump pulley, if it moves, you need a pump.  If it is solid, you probably need a power steering gear, there might be a stuck valve or restriction in it