Steering Noise Question

[fatman76]

I have a noob question on my power steering in my 2001 4.4i...

Turning left, when I get to about 80% I hear a groan. It gets worse the more I turn the wheel. To me it's tell-tale pump noise.

However, if you aren't moving Forward, it doesn't make this noise. So sitting in the garage last night I went 100% left and right and no noise. I do a slow donut in the culdesac and it groans (again, only turning left). No tapping, clicking, etc...just a groan. Don't typically hear it at any speed, but I also don't hit 80% unless parking, etc.

My steering is also stiff, but as it's a BMW it is hard to say if this is normal or not. My wife, who I finally inherited the car from, said this has been happening for about a year and she didn't think it was a big deal. Thanks babe.

I have changed the fluid several times, it's pretty clean. Filter doesn't look clogged. I leak oil (different problem) but don't ever see PS (ATF) fluid.

So...question is - how does the pump know what direction it's going? Am I "throwing parts" at it to just order the pump and put it on this weekend? Control arm possible? Stering rack maybe?

TIA - as you can tell I am grasping at straws...