Anyone got any tips? Are the quattro and fwd pumps different?

All of a sudden I have no power steering below 2k rpm. Car is making the typical groaning noise when turning. Fluid level is good and fluid looks clean/normal.

 

I changed the pump with a used one I got at a junk yard for $100. Works perfect.

It was pretty easy to change out. The 7/8" "bando" nut is on extremely tight and required an impact wrench, Even after penatrating oil on it for 24 hours.

I got scared when it started making a lot of noise and the fluid kept foaming. Turns out it was low on fluid and just needed to wait for it to unfoam and add some more fluid. The noise went a way.