I have a question about my a/c system. I had to change my a/c compressor in the summer, because it actually blew apart while driving. I changed it and the receiver dryer (I think, the silver canister) and also orifice tube (filter). My friend took to his shop and evacuated system and refilled. Ever since then at idle or low RPM like backing out of parking spot or even going straight it growls and makes the truck shake. I know its the a/c because it doesn't do it when its off. It doesn't do it all the time but most all. When it first happened I looked at the compressor and saw the green dye that had leaked out of relief valve. It doesn't do that anymore. There were metal shavings in old filter. Any help would be appreciated. Also it has rear air if that makes a difference.