My 1979 C-30 atomic-4 doesn't seem to want to stay out of gear. When warming up my engine (high idle/vidration), I constantly have to tap the shifter forward or reverse and watch the prop shaft to see if its out of gear. After warm-up it seems to work o.k.,though the neutral sweet spot seems to be very small. Shifting doesnt take great effort, just a moderate push or pull. Actualy, the reverse gear does take a bit of effort but i was told this is typycal for this model. There is plenty of oil in it. Any help is greatly appreciated. thanks