Power Steering Fluid problems of the 2008 Mercedes Benz R350

Groaning sound from steering while turning , leakage of power steering fluid requiring complete replacement of the steering box assembly.

I have an mercedes R350 model year 2008. It has 60,050 miles now but I have just been told that I need to replace the entire steering rack - $4000 quoted from mercedes-benz valencia in California. It has a fluid leak from the steering rack. I know that there is a NHTSA recall campaign (id number 08v682000) for certain 2008 mercedes gl, ml and r-class vehicles. I wonder mercedes-benz will replace the steering gears for my car with free of charge.