I don't know how hydraulic fluid would stay in the socket. My father has a 1985 300D and the Haynes manual for his car says to apply white lithium grease with a brush. The only lithium grease I had was in a spray can, so I also used heavy grease. I popped off the socket and put a good amount in each socket and popped them back together. Then I wiped off the excess. This seemed to quite down the linkage a bit.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section