gear cross shaft vibrates out of alignment

[taylor]

Hi All,

I've been having a recurring transmission issue. What's happening is really simple:

My shift lever is on the starboard side of the engine. When the engine runs, the reversing gear cross shaft slowly moves to port until the shift lever is touching the body of the engine. Once this has happened, it is impossible to shift out of forward.

At this point, I go below and push the cross shaft back to starboard (that is, I center it again), and it works fine until the engine has run for a bit again.

The solution hasn't been as simple as I thought it would be:

It seemed to me like the simple solution was to move the shift lever further to port along the cross shaft. This would prevent the cross shaft from itself being able to slide to port (because the shift lever would hit the engine before the cross shaft went too far out of alignment).

When I loosened the bolt that holds the shift lever, I found it impossible to budge the thing. I wasn't sure if it is just stuck or if something else is holding it in place. I just dont want to break something by hammering on it.

So, two questions:

1. Is moving the shift lever the correct fix/even possible? (And if not, what is? Should something be holding the cross shaft in place?)

2. If moving the shift lever to port is the thing to do, is there anything to do besides apply penetrating oil and whack the thing with a mallet? (Should it be possible to wiggle it aft and forward? Can I break something inside the reversing gear by hitting the shift lever toward port?)

Thanks for any thoughts y'all have!

[Mo]

On the pin that transverses the gear box there are bushings...have a look and ensure they are not worn out.

[taylor]

Hey Mo,

Are the bushings inside of the gearbox? Is the pin something different from the shaft which the shift lever attaches to?


Taylor

[Mo]

The shifter connects to a shaft that transverses the whole assembly...there are bushings at each end where it comes through the housing. Perhaps you could take a video or pics of what's going on and we can help more...

[taylor]

This is a picture of the reversing gear side of the engine. The arrows show which way the cross shaft is sliding.

Is there any way to reposition where the shift lever sits on the cross shaft? (ie move the shifter to where it wants to sit and then tighten it down on the still centered cross shaft?)

[hanleyclifford]

If you look in your parts manual page 129 at the exploded view of the shaft and the yoke it controls you will see a set screw (#32) which locks the yoke to the shaft so that it may not move.

[taylor]

Thanks Hanley, I checked and know exactly what you mean.

So that screw will hold the cross shaft (34) in place, but there is another issue, which is that the shift cable and its bracket will always want the cross shaft to move back to port, and they will be pushed out at an angle if i forcibly center the cross shaft without moving the shift lever (37) closer to center.

I tried loosening the other set screw (39), but the shift lever wouldnt budge. Any thoughts on getting the shift lever to move relative to the cross shaft?

[hanleyclifford]

Thanks Hanley, I checked and know exactly what you mean.

So that screw will hold the cross shaft (34) in place, but there is another issue, which is that the shift cable and its bracket will always want the cross shaft to move back to port, and they will be pushed out at an angle if i forcibly center the cross shaft without moving the shift lever (37) closer to center.

I tried loosening the other set screw (39), but the shift lever wouldnt budge. Any thoughts on getting the shift lever to move relative to the cross shaft?

Usually that connection is rusted fairly solid. The best thing you can do is re engineer the linkage so that the pull/push on the shift lever is parallel to the drive train. Could take some design and fabrication.

[taylor]

Okay, got it. In the interest of giving it a try, if I dab some penetrating oil on it and tap it with a hammer, is that likely to break anything? How rough can i get with it? And in the event I can free it, can the shift lever actually be positioned anywhere on the cross shaft? (Not sure whether the lever needs to be on those slots on the cross shaft.)

[Al Schober]

Taylor,
That cross shaft tends to get very corroded. Last rebuild I did, I looked through my parts pile and didn't find a shaft I wanted to reinstall. I'd installed new shifter seals, but didn't have a shaft I wanted to push through them. Bought the new stainless cross shaft from Mr Moyer. The pain of the price has since gone away, but I now look at that shaft and smile.
I haven't seen a cross shaft that tended to move either way. Offhand, I'm not sure what keeps it in place - I think it's the link to the fwd cone that limits the travel.
Perhaps you just have some loose set screws..
The shift lever transmits its oomph to the shaft through the half round key. The key should be completely covered by the shift lever, otherwise it can pop out. As long as you can't see a corner of the key, you're good.

[taylor]

Ah, okay. That makes sense.

So then, the course of action is 1. to fit something to the bracket so that the shift cable is further from the engine's center and 2. to open the reversing gear assembly and tighten up those set screws.

Thanks guys!

t

[taylor]

Fixed!

Hey guys, just an update:

I took the cover off the reversing gear (I was shocked by how clean and pretty everything was in there), and figured out the root of the problem:

The two set screws inside the reversing gear were tightened down, so when the cross shaft moved, it was disconnecting the yoke from the locking bar. So I loosened the set screws, slid the cross shaft to port until the shift cable was lined up straight, and then tightened the screws down.

Took her out today for a sail and everything worked great! (Good thing, too. It was windy!!)

[zellerj]

If you look in your parts manual page 129 at the exploded view of the shaft and the yoke it controls you will see a set screw (#32) which locks the yoke to the shaft so that it may not move.

I had a hard shifting issue and my set screw was loose. Thanks Hanley for the tip to tighten everything up.

Jim