2001 S80 2.0 T transmission problem
 

I'm having the harsh shifting/disengadgement problem with the trannyof my 01 S80 2.0t A/T. I can't remember the tranny model but I know the tranny oil uses the jws3309 specs. My problem is that after changing the oil, the harsh shifting is still there. I wasted my money on changing the oil. Now the dealer is telling me that i have to change the CONTROL VALVE BODY. They said that there is some plastic parts broken inside. I was wondering how come plastics are used in the tranny. Any comments or advice what to do. I feel sometimes that the dealer doesnt have any idea what they are doing, they are just guessing on what to do, they are just sucking my money like a vacuum.