Shuttle Shift Repair KM554

[3RRL]

While building my barn pad, all the strenuous digging, ripping, fel and boxblade work has caused my shuttle shifter to not work. I bumped into a rock pile in reverse with the boxblade and the shifter got stuck. First time that's ever happened after 345 hours. After wiggling it I finally pushed it into forward and started going again, only to find out it would not shift into reverse! I could move the shuttle lever freely but it was not engaged to anything anymore...just flopped around, but the trans was stuck in forward.

So I drove the Kama back to camp to see what the problem was. Thoughts of stripped gears, broken shifter forks etc. dance in my head. To compound matters, it was raining pretty hard by now.
I was hoping it would be something easily repaired, and not a major thing. Hoping maybe it would be something that was minor and could be made better by fixing it. So I took the shifter plate that held the 4 wd and shuttle shift levers off.



This is what it looks like under there. You can see the shifters have ball shaped actuators that ride inside a channel. The channel is attached to the gear clusters and move them from one position to the other.



Didn't look like anything was broken? You can't see it very well, but the slot for the shuttle lever is closest to the bottom in that picture. For some reason, the slot walls had a big 1/2" chamfer on the right side.

 

[3RRL]

After checking and looking for what was wrong, I decided to see if I could move the gear clusters back and forth by hand. They slid freely back and forth. The compression dowel pins were not sheared and everything looked and felt solid in there. So I moved the gear cluster to where it would be in "reverse" and started the tractor with the lever plate off so I could see in there. The gear clusters don't spin with the clutch in so I put it in gear and slowly slipped the clutch a little and the tractor started to back up just fine?
Then I moved the gear cluster into the "forward" position and slipped the clutch and it started to go forward just fine. This greatly relieved my fears that something major was NOT broken. Now to find the problem.
BTW, don't let the clutch out when it's in neutral with the cover off. It will spray oil all over you! Don't ask how I found out.

Anyway, I shut the tractor off again and started looking for the problem. It was obvious that the engaging lever had jumped out of the shifter slot on the gear cluster. In looking for sign, I noticed wear on the shifter lever and also on those chamfered down walls of the gear cluster slot.



The engaging lever was not in the middle of the slot, but over to the side where the slot walls were cut down. So it was barely engaging in the first place, and over 345 hours of use, both slot and lever had worn enough to slip by the chamfer walls on the slot.

 

[3RRL]

I made the determination to center the shifter engagement by welding a dogleg to it, where it would fully engage with the slot on the gear cluster.
I started by welding a small piece of steel to the side of the lever.



Fixtured it with vise grips.



And welded it with my Lincoln arc welder. Too bad I had to do this at camp, or it would have been an easy weld with my TIG welder at home. But anyway, it had to do and was good enough.

 

[3RRL]

After welding, I ground down the weld to the shape of the lever, leaving about 1/2 inch sticking out to the side of it. This should fit nicely into the center of that slot.
Sorry these pictures did not come out crystal.





Now I realize that if I ever had to change out the lever, it would not fit through the slot on the plate as it is now, but so what. The good news is it worked perfectly and smoother than before. It appears that it's been wanting to slip over the side and that jammed it up a little before. Now it does not do that. After putting it all back together (and cleaning up a little oil spill) the first thing I did was back it into that rock pile again ... no problem now.
Thanks for looking...

 

[DwayneB]

Nice job there Rob. It's spring here finally and I hope to get back to breaking things soon myself!!!!

 

[Soundguy]

Nice job!

Soundguy

 

[greg_g]

Or - you could have just pushed the shift finger down farther into the fork rails. Take a look at pg 35 in your parts manual. Insufficient depth of that finger on lever #2 (into fork #62) may have been what tore your rails up in the first place. Locate screw #8, it's hiding under cover #6. I know this book doesn't specifically cover shuttle shift models, but this particular diagram is representative of the problem you describe. Part #8 performs an identical function; it is a set screw that limits up/down travel of the lever #2 against spring #5. Alternatively, you can bore a new hole for pin #3. Before I had even a dozen hours on my KM454, I had to release that set screw - and shove the lever down to the limit of it's travel against the spring tension, then dog the set screw back down. Been just fine for the last 200 hours.

Good work curing the symptoms. But from what I read, you may still have missed the cause.

//greg//

 

[Ranch_Hand_Supp]

Good job Rob !!!.....

Looks like you dialed into what it was missing/needed.

Ronald
Ranch Hand Supply

 

[3RRL]

Thanks guys, that sure cured the problem and made it shift better without that hesitant "grab" as before.
I checked to see if the depth was not sufficient and if that was the primary cause, and it wasn't the problem. Otherwise my repair would have popped out too, if the lever wasn't deep enough into the slot.
In Greg's attachment, the part he refers' to ... #62 has that slot on the top of it. That's where the engagement takes place between the 2. Imagine if the end of that slot, the vertical walls, had a 45° angle cut on them to the bottom of the slot. So the vertical walls on the end of the slot were missing. The side of the ball on the shifter lever was barely making contact with those angle walls and they had worn down to allow it to slip past.

From the photo in post #2, you can see where the lever was skidding sideways around those 45° walls. The manual does not show that slot with 45° walls on it, rather it is shown straight up and down. The 4x4 lever slot walls were not like the shuttle shift. It was like the manual shows, straight up and down. Funny thing is that the angle part looked like it was cast that way. I see now that in the photo, the walls don't look angled...you can't see it in that view very good, but those are on a 45°.