1985 F250 6.9 diesel
 

My 6.9 is ailing. It has a thudding sound coming out of the breather. Kind of sounds like a broken diaphram that is leaking air. I was told maybe a wrist pin was coming out. I put a stethoscope on the block from front to back, top to bottom and cannot pin it down to a particular cylinder. I wonder if its a lifter that is stuck and a valve is not opening/closing correctly. I took the valve covers off and there is one push rod that has a lot of play.

When I changed the oil after this started what looked like a keyway key was stuck to the magnet on the drain plug. My other thought was it was out of time because this key came out and one of the gears turned a little. It runs, maybe a little power loss, but idles smooth as a babys bottom.

Help!!!!!!!!!!!!!!!!!!