I have a 1986 Mercury 45 HP Serial #A949831. On way to lake last weekend was hit from behind by a car. Motor is on a transom saver so most of the impact was on the prop. Hard enough impact to feel through trailer but no visual damage. Motor will start and run normally but stuck in forward gear. No neutral or reverse gears. Have removed lower unit and shift cables operate freely. Please reply with what I should try next. Thanks