I removed my ski platform and was close to my drive and it seems that when you turn the drive it has alittle play in it.It has a frame that holds the the drive and has a bearing on each side and one on the top.They all have a zerk fitting and the side ones have wires on the back,one of the side bearings is loose.What is it and is it tough or expensive to fix.It is a 1987 mercruiser engine(300 Tempest)and a Alpha One drive 