The ATF blends have changed in the last few years and now have additives that are not healthy for the seals in you power steering system. But, I wouldn't think it would cause the system to whine.

I have used Power Steering fluid that I buy in a one quart container at the auto supply. I've been doing this for 8 or 10 years with great success. It's a little expensive, but a pittance compared to what MB power steering components cost.

Good luck,