I have a 95' Mercury 25 hp with a bent prop shaft. The shaft looks like it is bent with a twist in the splines on the out side of the lower unit. I can take the prop off but I can not get the thrust hub off. I have a Clymer manual and it says you can take the prop shaft off without taking the lower unit off. Is this true or should I take it off to be more able to replace any parts the bent shaft may have ruined. Thanks!!!