Multiple problems with Yanmar shaft drive

[Palarran]

I'm looking for some advice with a few problems my port engine is experiencing. The engine is a 4JH4-TE with KM4A transmission. This is a shaft drive with Variprop feathering propellers.

My good friends are using Palarran right now and they have noticed 3 problems.

1 - The engine is vibrating when the rpm's are above 2200. It isn't a real bad vibration and only noticeable both visually and audibly when you have the engine cover open.

2 - There is a diesel film on the valve cover

3 - Most concerning - There is a slight movement in and out of the shaft to the transmission when shifting into and out of drive. This movement is so slight it takes a while to spot and probably isn't more than 1/4"

My friends had a Greek mechanic look at the motor today. His diagnosis is:

1 - The vibration is from a misalignment of the shaft and motor. I had new dripless shaft seals put on this winter and they needed to replace the coupling. I had specifically asked the technical director if the mechanic checked the alignment between the two and he said absolutely - so that means maybe. I can't imagine what else would be causing the vibration unless something caught the prop, but that is not likely.

2 - The oil is from a leak at the turbo. My friends can't see any leak and said the film is very slight, with no diesel accumulation anywhere. Is this a problem that can wait until I return?

3 - The Greek thinks the cone clutch is going bad on the transmission. The motor and transmission have 900 hours on them. The motor shifts in and out of gear very easily and to my knowledge doesn't make any noise at all. I've been replacing the transmission oil as recommended. Again, my friends say the movement is very slight. They are concerned that the transmission would break at the exact wrong moment like when docking. I don't have any knowledge of the inner workings of these transmissions to know if there's a problem here.

Any advice on these three problems would be greatly appreciated.