M6040 synchro shuttle question

[Fedup]

I had some questions asked of me today concerning what I believe to be a shuttle problem on this tractor. Having never been into one I started doing some research and concluded that it's actually "synchro" in name only. It has dual wet clutch packs mechanically engaged in place of a synchronizer. An interesting concept I have never seen before.

My question is this. Considering it's a wet multi disc assembly, would it hold up well if used without clutching when changing directions? Not that I suspect this was the case here. It's just a question that comes to mind. I'm not suggesting anyone should operate one that way, it's NOT a power shuttle, but it seems to me this design would take more abuse than conventional synchro rings. I do know that a good many "operators" tend to shift directions a bit before the tractor comes to a complete stop, so maybe this would be a little tougher in that arena?

 

[JasonW]

First off is it a synchro shuttle or hydraulic shuttle? What’s the model of tractor?

Synchro shuttle is a dry clutch that you have to clutch for direction changes.

Hydraulic shuttle is a wet clutch that you don’t have to clutch for direction changes.

Both have to clutch to shift gears.

Synchro is named so you can clutch and shift forward to reverse without a complete stop. My MX5100(dry clutch) is a partially synchronized transmission. Forward to reverse, and 3rd and 4th gear are synchronized while 1st and 2nd gear are not.
Older (lesser model transmissions) were not synchronized forward to reverse or any other gears.

 

[Fedup]

I guess we're not quite on the same page here. It's called a "synchro shuttle", as opposed to a power shuttle. It has a dry clutch, and a mechanical shuttle. It's just not a synchronizer. It's actually clutch discs and plates.

 

[PoTreeBoy]

I guess we're not quite on the same page here. It's called a "synchro shuttle", as opposed to a power shuttle. It has a dry clutch, and a mechanical shuttle. It's just not a synchronizer. It's actually clutch discs and plates.

I had a similar question on an M7040

Which M7040 am I driving?

I do a little volunteer work at a horse rescue place. Mostly manipulating manure, but the pastures are getting out of hand so the other day I thought I'd do something about it. They have an M7040 with FEL and brush cutter that I've used a little. My question is how can I tell if it has...

www.orangetractortalks.com

It turned out to have the hydraulic shuttle. The synchro shuttle model has a single disk dry clutch and a wet disc type synchromesh F-R shift. Gears 1-4 are synchronized, but range shift is not. So the foot clutch has to be used for all shifting, but the tractor can be moving for all but range shifts.

 

[JasonW]

I guess we're not quite on the same page here. It's called a "synchro shuttle", as opposed to a power shuttle. It has a dry clutch, and a mechanical shuttle. It's just not a synchronizer. It's actually clutch discs and plates.

Reread my first post. A power shuttle or power reverser is John Deere’s wording similar to Kubotas hydraulic shuttle and they operate similar as you don’t have to clutch for direction changes.
Again what model tractor are you referring to? If it’s a dry clutch, it’s a synchro shuttle that you have to clutch it change directions.

 

[SDT]

I had some questions asked of me today concerning what I believe to be a shuttle problem on this tractor. Having never been into one I started doing some research and concluded that it's actually "synchro" in name only. It has dual wet clutch packs mechanically engaged in place of a synchronizer. An interesting concept I have never seen before.

My question is this. Considering it's a wet multi disc assembly, would it hold up well if used without clutching when changing directions? Not that I suspect this was the case here. It's just a question that comes to mind. I'm not suggesting anyone should operate one that way, it's NOT a power shuttle, but it seems to me this design would take more abuse than conventional synchro rings. I do know that a good many "operators" tend to shift directions a bit before the tractor comes to a complete stop, so maybe this would be a little tougher in that arena?

Sounds like a hydraulic shuttle to me.

Yes, tractors with hydraulic shuttle transmissions can be routinely reversed without stopping.

 

[mcmxi]

Sounds like a hydraulic shuttle to me.

Yes, tractors with hydraulic shuttle transmissions can be routinely reversed without stopping.

To add to this, I have an M6060 and the owner's manual specifically states that "The hydraulic-shuttle shift lever may be shifted while the tractor is moving slowly". I don't shift F>R or R>F unless I'm almost stopped.

 

[SDT]

To add to this, I have an M6060 and the owner's manual specifically states that "The hydraulic-shuttle shift lever may be shifted while the tractor is moving slowly". I don't shift F>R or R>F unless I'm almost stopped.

View attachment 140389

Good practice.

 

[Fedup]

I guess I didn't quite make it clear enough. This tractor does NOT have a power shuttle. It has what is called a SYNCHRO shuttle. At least that's what Kubota chooses to call it. I wasn't aware there was design such as this. Many synchronized shuttles out there on many brands of tractors. (I've been into more than one so I know what they look like and how they operate) This one does not use a sychronizer, but two stacks of wet clutch plates and discs instead. New concept ( to me anyway). I was merely hoping for any feedback from those more familiar with this design, not a crash course on how to use a power shuttle.

 

[mcmxi]

I guess I didn't quite make it clear enough. This tractor does NOT have a power shuttle. It has what is called a SYNCHRO shuttle. At least that's what Kubota chooses to call it. I wasn't aware there was design such as this. Many synchronized shuttles out there on many brands of tractors. (I've been into more than one so I know what they look like and how they operate) This one does not use a sychronizer, but two stacks of wet clutch plates and discs instead. New concept ( to me anyway). I was merely hoping for any feedback from those more familiar with this design, not a crash course on how to use a power shuttle.

Kubota is very clear on the synchro shuttle i.e. you need to depress the clutch when shifting between F & R. Obviously, with the hydraulic shuttle you don't need to depress the clutch when shifting between F & R. If you choose not to depress the clutch when shifting from F to R or R to F that's your prerogative, but I sure wouldn't.

 

[PoTreeBoy]

I guess I didn't quite make it clear enough. This tractor does NOT have a power shuttle. It has what is called a SYNCHRO shuttle. At least that's what Kubota chooses to call it. I wasn't aware there was design such as this. Many synchronized shuttles out there on many brands of tractors. (I've been into more than one so I know what they look like and how they operate) This one does not use a sychronizer, but two stacks of wet clutch plates and discs instead. New concept ( to me anyway). I was merely hoping for any feedback from those more familiar with this design, not a crash course on how to use a power shuttle.

If your M6040 has two hydraulic (wet) clutch packs, it is NOT a synchro shuttle, it is a hydraulic shuttle. Look at post #4, does your shuttle lever have the loop or just a straight lever?

How do you know the tractor has two wet clutches, do you have it apart or are you looking at diagrams?

Does the tractor have a Synchro-Shuttle decal on it?

 

[PoTreeBoy]

I guess I didn't quite make it clear enough. This tractor does NOT have a power shuttle. It has what is called a SYNCHRO shuttle. At least that's what Kubota chooses to call it. I wasn't aware there was design such as this. Many synchronized shuttles out there on many brands of tractors. (I've been into more than one so I know what they look like and how they operate) This one does not use a sychronizer, but two stacks of wet clutch plates and discs instead. New concept ( to me anyway). I was merely hoping for any feedback from those more familiar with this design, not a crash course on how to use a power shuttle.

If you happen to be looking at a diagram, those two things circled in green are not shuttle clutches. They are wet-disk synchronizers. I suppose they are used instead of more conventional synchronizers in order to withstand more abuse.

 

[Fedup]

If you happen to be looking at a diagram, those two things circled in green are not shuttle clutches. They are wet-disk synchronizers. I suppose they are used instead of more conventional synchronizers in order to withstand more abuse.

View attachment 140403

Yes, that's what I'm dealing with. Strictly mechanical. As previously stated, I'm hoping for some feedback on how these hold up as compared to conventional sychronizers with the facing lined rings? I have never seen this before and am curious what experiences others have had with them? I'm sure SOMEONE out there has been into one (or more) at one point or another. It seems to me this could be a longer lasting system, but can't help wondering what others have found? Anyone have any failures to report?

 

[PoTreeBoy]

Yes, that's what I'm dealing with. Strictly mechanical. As previously stated, I'm hoping for some feedback on how these hold up as compared to conventional sychronizers with the facing lined rings? I have never seen this before and am curious what experiences others have had with them? I'm sure SOMEONE out there has been into one (or more) at one point or another. It seems to me this could be a longer lasting system, but can't help wondering what others have found? Anyone have any failures to report?

My only hands-on experience was with the hydraulic-shuttle model and it never gave a problem. I was amazed to discover my foot was controlling a hydraulic system, it felt just like a dry clutch. I don't recall any problems with the synchro-shuttle being mentioned on this forum. That said, the hydraulic-shuttle would be preferable and Kubota discontinued synchro-shuttle on the M6040/7040's successors M6060/7060.

In your first post you mention some problem that you believe to be shuttle related. If you give more details, someone on here may be able to assist.

 

[Fedup]

The problem with this particular unit (as it was explained to me) goes something like this. The tractor has a loader, is used for farm chores, hay machinery, field mowing, that sort of thing. Recently it has developed this condition where the shuttle lever supposedly won't fully engage in reverse, at least the detent doesn't lock in. Apparently it does drive in reverse, it just doesn't "feel" right. Then when shifted into forward, it "feels" like it's engaged and locked in, but when you let the clutch out it loads up and stalls the engine. I haven't been out there yet so I have no more information than that. Planning a visit in the next day or so for a first hand evaluation.

Having zero experience with this model, the first thing I did was locate and begin studying the WSM to see what all is involved and how it's all put together. (and of course, how it might come apart) That's how I came to the realization of the clutch discs in the mix. That prompted me to reach out to see if anyone has had any of this type unit apart for any reason. Maybe there's something to learned from that. So far, not much.

My first thought in this case is that something is wrong on the reverse stack of discs. That could affect travel of the collar and fork, not letting it go far enough to catch the detent. Something jammed up in there could also keep reverse (at least partially) engaged so if forward is selected it would be trying to go both ways at once. Once I actually see and attempt to drive it I'll have more and possibly better details.

 

[mcmxi]

Recently it has developed this condition where the shuttle lever supposedly won't fully engage in reverse, at least the detent doesn't lock in. Apparently it does drive in reverse, it just doesn't "feel" right. Then when shifted into forward, it "feels" like it's engaged and locked in, but when you let the clutch out it loads up and stalls the engine.

The WSM has a section on adjusting the shuttle lever to properly align the F, N & R detents via a lock nut on the lever cable. If the shuttle lever won't engage the reverse detent perhaps this is the place to start. Obviously I'm just guessing here based on your description of the issue.

 

[PoTreeBoy]

The WSM has a section on adjusting the shuttle lever to properly align the F, N & R detents via a lock nut on the lever cable. If the shuttle lever won't engage the reverse detent perhaps this is the place to start. Obviously I'm just guessing here based on your description of the issue.

The WSM page 3-S8 has a procedure for adjusting the neutral position. I'd start there, but I'm also guessing.

 

[Fedup]

Well, no need for more guessing. I was down to the tractor today and determined there is no adjustment that will fix this problem. I was able to drive it around for a while and after about ten minutes of careful back and forth operation the problem reared it's head. At first it seemed perfectly normal and operated just as one would expect. But then I noticed a shudder when taking off in forward. I could feel the tractor try to stop then break free and move forward like it should. Next couple tries and it got a little worse, then once or twice it actually pulled the motor down to a grunt when taking off, then popped loose again. Then an interesting thing happened. There is a chain hanging on the box blade top link bracket that was clanging when I changed directions so I stopped to secure it better. I put the shuttle in neutral, and got off to do that, and while I was in the process, the tractor started moving backwards. The reverse portion apparently had decided to grab even though the linkage was in neutral. It was only idling and in a low gear as well, so it didn't get far before I stepped clear, but it was indeed a surprise.

So now I know what to do next. Split it and get the shuttle out on the table. Over the next few days they will get a spot cleared out, I will get some stuff moved down there to split it with, and we'll see what's going on there.

Again, I wonder if anyone who works on these tractors had one apart and if so, what did you find?

 

[PoTreeBoy]

Well, no need for more guessing. I was down to the tractor today and determined there is no adjustment that will fix this problem. I was able to drive it around for a while and after about ten minutes of careful back and forth operation the problem reared it's head. At first it seemed perfectly normal and operated just as one would expect. But then I noticed a shudder when taking off in forward. I could feel the tractor try to stop then break free and move forward like it should. Next couple tries and it got a little worse, then once or twice it actually pulled the motor down to a grunt when taking off, then popped loose again. Then an interesting thing happened. There is a chain hanging on the box blade top link bracket that was clanging when I changed directions so I stopped to secure it better. I put the shuttle in neutral, and got off to do that, and while I was in the process, the tractor started moving backwards. The reverse portion apparently had decided to grab even though the linkage was in neutral. It was only idling and in a low gear as well, so it didn't get far before I stepped clear, but it was indeed a surprise.

So now I know what to do next. Split it and get the shuttle out on the table. Over the next few days they will get a spot cleared out, I will get some stuff moved down there to split it with, and we'll see what's going on there.

Again, I wonder if anyone who works on these tractors had one apart and if so, what did you find?

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