Power steering assist?

When I first start up in the morning the power steering seem to work quite well; fair amount of power; not too much effort to turn the steering wheel. After warming up, the power steering requires much more effort to turn the wheel. Any ideas as to what's happening? Its a 2001, BTW

I have seen this happen if the fluid level is too high. Also, what fluid are you using, and how old is it?

Fluid is whatever was in it when I bought it & I'v never changed it. Maybe I'll try changing it out.

All I know is my 1990 had power steering that could be turned with 1 finger all day long; hot or cold.

I have the same problem, sorry to hijack but maybe this will shed some additional light...

I just swapped boxes and I have similar problems, however left of center and turning left it seems almost sticky if I pulse my steering imputs (stopping and starting). THis only happens once the fluid is warm. To the right it works better but is still slightly noticible. I'm using what I suppose amounts to store brand power steering fluid which from reading the bottle is petroleum based like the manual calls for.

Curious though as to why overfilling would cause a problem-not that I doubt, just curious. Hope the additional info and angle help

Mine is the same in either direction....Unless the fluid is really contaminated, (like yours wouldn't be, being a new steering box) I can't imagine what would be wrong with the fluid. The fluid is used to provide pressure and if the pump is making the pressure, then everything should work. Or maybe the PS pump is bad? Do pumps go bad and not growl? Provide some pressure but not enough to do the job; e.g. go into bypass but not hiss? Anyone??

mine does growl, it seems to growl more lately hmmmm