Problem with rack and pinion
 

I purchase my 2008 ML350 (pre-owned certified) in 2010 from a dealer in white plains ny. Since that time, I've taken the truck back several times for a wheel alignment, and also asked them to check the front end for looseness, and play in the steering wheel, especially noticeable on the highway. Each time I got the truck back I was told that everything was ok.
Well the truck is back at dealer with the same problem ... and now that the warranty has expired, they find an internal problem with the rack and pinion, which is causing the loose feeling, and play in the steering wheel. I am certain that this is a problem the should have been found while the vehicle was still under warranty ... now they want to charge me over $2000 to fix. Does anyone know of any issues or campaigns with the 2008 rack and pinion?