Power steering issue

[amebb]

Hi,
I have a bmw e53 x5 autmatic diesel 2003 model.


My issue is that my steering feels heavy at times.

Lets say if i am driving i can turn the steering wheel with no issues a smal amount. But, lets say if i have to do a full lock on either side, it feels like there is some resistance on the wheels that makes turning harder or heavier.


There is no loss of power steering fluid and i have drained most of the fluid out and replaced it with fresh new fluid today.
This made very little difference to the steering.

I am not getting any noses from the pump like grinding or anything else.


Has anyone else experienced these issues before or does anyone know what i need to check or fix?


Thanks for your help.