Shuttle Shifter Repair - Kama 554

[3RRL]

While building my barn pad last year, all the back and forth digging, ripping, fel and boxblade work did a number on my shuttle shifter. 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 itself was stuck in forward gear.

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 shifter levers have ball shaped actuators that ride inside a channel. The channel is attached to the gear clusters and when you move the shift lever, it moves 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.
Remember this photo below for later.



Rob-

[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. Proof of them slipping out and explaining why the shift lever didn't engage.



Checking it further, I noticed the engaging lever was not located in the middle of the slot, but way over to the side where the slot walls were chamfered 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 on those walls.
Rob-

[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. In a previous board, Brad had asked about moving the slots in the shifter plate to center them up better. I suppose that could be done as well as bolt the shifter plate over to one side as much as slop allows, but I decided on another avenue of repair.

I started by welding a small piece of keystock 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 it turned out 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, but they are a year old now.



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.
Rob-

[3RRL]

In that earlier thread, I borrowed a photo from Brad which has a better view of the walls I was talking about. It is marked up to show the missing corners or the chamfers on my Kama. Look at the yellow mark up on the shifter slot. I have (tried) to draw where the chamfers are on the walls of the slot which allowed the shifter ball to jump out slot. Those corners were missing there on mine.



I see on Brad photo of his Kama, there is evidence of the shifter rod hitting near the middle of his slot, so his slot is the way it's supposed to be. They are as shown in the manual.... square with no chamfers, so he has no problems.

As far as shifting the cover plate, note that the gear cover has a guide plate underneath held on by some bolts.



It is possible to scoot that over a bit as that piece guides the shifter lever. But in my case, I did not think it would move enough to fully engage, leaving me with a marginal engagement, just waiting to wear out again. You'd have to move it towards the middle a good 3/8"" or so. Mine was just nicking the edge of the slot/chamfer to the edge of the shifter. From what I could tell, the shifter piece was not too short, just offset enough to slip over that big 45° chamfer on the gear cluster slot to allow all this to happen.

Well, it's been over a year since I did that field repair now, and 155 hours later. The shuttle shifter has been working smoothly with no recurring problems. I know I may not always approach a repair like that in a conventional way, but I make decisions on the spot. I try to do what I know will get my tractor back to working again with the least amount of fiddling around. At least that's how I see it.
Thanks for looking and SPECIAL thanks to Brad for letting me share your photo.(even before I asked ;D)
Rob-

[bracabric]

Wonderful diagnostic and imaginative repair Rob, not for the first time, you are an inspiration !!

Dick