If it were linkage..hard metal to hard metal, I'd think it would be constant. Inside the lower unit is the drive shaft, some seals and bearings, the prop shaft and the drive shaft pinion gear which drives the rear of F and R gears.
F and R gears spin as long as the flywheel is turning, hard metal to hard metal.
The prop shaft couples to those gears via a "shift dog" which is locked to the prop shaft for rotational aspects but the locking mechanism is spring loaded and has a slot in the prop shaft whereby the dog can move back and forth. The dog is what connects the spinning F and R gears to the prop shaft.
The movement is controlled by your shift shaft which connects in the LU to a shifter cam. This cam has 3 detents representing F N R gear positions. On the front of the prop shaft is a "cam follower" which rides in and out of these detents as one selects a gear. Inside of this cam follower is a spring that pushes against the clutch dog and this spring pressure either allows the dog to rest in the rear of F gear, with a little more pressure in mid position for N gear where the teeth on the dog don't connect to F or R gears, and the third follower position with maximum pressure against the spring, pushes the dog to the rear and engages R gear.....that's how it works.
I don't know what happened when you hit the bar nor what you did then or later but my guess is that the dog is damaged. I'd do some general testing to get a better feel of what it is and isn't doing or supposed to be doing before I tore into it but removing the prop shaft isn't that bad of a job...just keep track of what you take out and where it was...a parts breakdown picture helps in doing that. The teeth on the F and R gear are hardened steel and are probably ok. I think the dog is bent or has damaged teeth and that accounts for why sometimes it works and sometimes it doesn't.
If it's like I'm thinking, a couple of bolts hold the R bearing carrier into the LU housing...Pulling that out allows you to work the prop shaft out...being careful to watch for shims and remember where they were...shims, large like 4" in diameter.....F gear and any shims associated with it should stay in the LU in position if you are careful...even if it falls down no biggie to put it back into its bearing in the nose of the LU.
With the prop shaft in your hand you can examine the cam follower bullet nose for a non marred blunt conical end and examine in particular the clutch dog and the front and rear gears on it.....also checking that forcing against spring pressure, the dog slides easily back and forth on the prop shaft. If the gears on the dog are dinged up pretty good you might check the teeth on the back of F and R gears too. Dealing with gear issues on a boat can be super frustrating, especially when you're out on the water and just want things to run smoothly. Sometimes it’s a minor adjustment, like cable tension, but other times it’s deeper—like wear and tear on the equipment. Before throwing cash at a repair, it’s smart to dig into what others have experienced with similar setups. Sites like
Intoxalock reviews can be helpful for spotting patterns in equipment reliability or finding out if a specific part is prone to issues. A little research now could save a lot of headaches later!
