squeaking/ squealing front end on 2006 Mercedes-Benz CLS500

I have a CLS500 and the front end squeals/squeaks on bumpy roads.Also a squeaking noise when turning left or right, and when you depart the vehicle the front creaks! The dealer says its the ball joints..they,re tight but he said they must out of grease...need to replace. I returned home and bought a needle for grease guns and injected grease into the joints. noise still persists. Afriend of mine is a mechanic and says its not the ball joints. Does anyone have the same problem?

Asked by for the 2006 Mercedes-Benz CLS500
I had the exact same issue. Other shops said ball joints look good. Took it to MB dealer and even though no leaking ball joints, no rubber boot damage to ball joint. My lower joi ta were creaking. The noise escalated pretty quickly once it got cold. I live in Maryland. I use EuroMotor cars. They know their stuff. Im positive the noise is related to ball joints.