08 f250 lower unit not engaging

[eric.101]

Installed used 08 f250 on boat went to test it and lower unit wont engage.It shifts on top of motor forward and reverse but not at the prop. Prop spins slowly in forward direction at idle but will stop with foot presure and has no change when I shift into forward or reverse.

[Aleutianwest]

Not going into gear

Grab onto prop shaft and see how far goes in and out if lots of play bearing carrier has back out

[eric.101]

no in and out play on shaft.

[Aleutianwest]

shifter

can you feel the shifter shifting at the prop if not you missed the shift rod connecting to lower unit

[rodbolt17]

that would be my guess.
someone changed the water pump,missed the splines on reassembly and never checked it.

[eric.101]

Yup that was it. Dropped lower unit reconnected it and shifts fine. THANKS