M7040 hydraulic clutch

[gwdixon]

OK, my first post on this problem died a "zero reply" death so maybe this basic question will get somewhere.

For those M owners with a "hydraulic shuttle shift", does the tractor move a bit when the lever is shifted into F or R while the transmission (gear shift) is in neutral?

My M7040 creeps about an inch and then stops both in F and R as if the gears are very slightly and momentarily engaged. No noise, just a slight movement.

The movement might be a reaction to the viscosity of the oil but it creeps whether warm or cold.

Six months and 170 hours on the tractor so if warranty work is needed it should be done soon.

Looking forward to your replies and expertise.

 

[3BPercherons]

Haven't noticed that behavior from my M6040.

 

[rcireland]

Haven't noticed any movement from my M6040 in 275 hrs.

 

[Doug_D]

None that I have noticed. That sounds like a linkage\cable adjustment.

 

[big bubba]

my 7040 needed the hyd shuttle linkage (under dash) adjusted from the factory, apparently a common qc problem....i'd let your service dept know on record for any warranty purposes, they can walk u through adj if it's needed. my 8540 did not have your described issues. good luck bb

 

[gwdixon]

Update:

Called two Kubota service departments in my area. Neither had a solid idea about the problem.

One said that he had heard of such problems individually but not together (grabbing clutch, hydraulic valves of the shuttle shift not closing and causing creep).

The second said that the main clutch is dry rather than wet. The wet clutch is operated by the shuttle shifter and the dry clutch by the pedal.

He suspects that slipping the clutch has caused "hot spots" and eventually they will wear flat again. He strongly advised against slipping the clutch to hold tension on a tree. No speculation about the creep.

The second dealer has rental return M8540s on his lot and suggested that I come in and drive them around to see if they have the same behavior as my M7040. Apparently the two tractors use the same transmission/clutch arrangement.

Please continue to provide information through this forum. The more that is known will help me deal with this issue.

 

[big bubba]

mr dixon: sounds complicated w/a lot of different views. you might run this by central k tech support: david haggarty @ 817 571 0900 has been the most helpful to me on these issues. yes, there's also an actuator valve involved in the mechanism. i'd be wary of service rep quick fixes. good luck bb

 

[rjkobbeman]

Full disclosure: I am not a Kubota mechanic (not a mechanic of any kind NOW)

However, this sounds like a syncronizer sticking. If you were shifting the shuttle from f/r into neutral and it was sticking I would think something in the hydraulic shuttle was not disengaging properly. However, since you are in neutral in the main gearbox and you are putting the hydraulic shuttle from neutral into f/r, it is the main gear box that should be freely rotating. Something is grabbing. If a syncronizer was grabbing on to a gear, this would be the behavior (if this is in fact the problem -- which it may not be). A shift collar that is engaging the syncro would cause the grabbing. An improperly adjusted shift fork could be causing the problem.

An improperly adjusted shift fork can cause your tractor to pop out of a gear and cause undo wear (wear out) the syncro that is grabbing.

Playing with the main shift can test for what I have explained. Using the main shift, find all of the "extreme" boundaries of neutral -- meaning, move the shifter towards a gear but do not actually go into the gear. (You will see there is a lot of play in neutral.) At each of the extreme locations, retest going from netrual to f/r in the shuttle. See if one or more of the extreme locations makes the problem better and/or worse.

 

[gwdixon]

Full disclosure: I am not a Kubota mechanic (not a mechanic of any kind NOW)

However, this sounds like a syncronizer sticking. If you were shifting the shuttle from f/r into neutral and it was sticking I would think something in the hydraulic shuttle was not disengaging properly. However, since you are in neutral in the main gearbox and you are putting the hydraulic shuttle from neutral into f/r, it is the main gear box that should be freely rotating. Something is grabbing. If a syncronizer was grabbing on to a gear, this would be the behavior (if this is in fact the problem -- which it may not be). A shift collar that is engaging the syncro would cause the grabbing. An improperly adjusted shift fork could be causing the problem.

An improperly adjusted shift fork can cause your tractor to pop out of a gear and cause undo wear (wear out) the syncro that is grabbing.

Playing with the main shift can test for what I have explained. Using the main shift, find all of the "extreme" boundaries of neutral -- meaning, move the shifter towards a gear but do not actually go into the gear. (You will see there is a lot of play in neutral.) At each of the extreme locations, retest going from netrual to f/r in the shuttle. See if one or more of the extreme locations makes the problem better and/or worse.

Will try that and report back. Thanks.

 

[red4now]

No symptoms like that on either the M7040 (over 600 hours) or the new M8540 - just over 60 hrs. Have heard of that linkage adjustment situation but this sounds like something different. Taking the M8540 in for the initial service next week so will ask the mechanic there if they have heard of this.

 

[gwdixon]

Full disclosure: I am not a Kubota mechanic (not a mechanic of any kind NOW)

However, this sounds like a syncronizer sticking. If you were shifting the shuttle from f/r into neutral and it was sticking I would think something in the hydraulic shuttle was not disengaging properly. However, since you are in neutral in the main gearbox and you are putting the hydraulic shuttle from neutral into f/r, it is the main gear box that should be freely rotating. Something is grabbing. If a syncronizer was grabbing on to a gear, this would be the behavior (if this is in fact the problem -- which it may not be). A shift collar that is engaging the syncro would cause the grabbing. An improperly adjusted shift fork could be causing the problem.

An improperly adjusted shift fork can cause your tractor to pop out of a gear and cause undo wear (wear out) the syncro that is grabbing.

Playing with the main shift can test for what I have explained. Using the main shift, find all of the "extreme" boundaries of neutral -- meaning, move the shifter towards a gear but do not actually go into the gear. (You will see there is a lot of play in neutral.) At each of the extreme locations, retest going from netrual to f/r in the shuttle. See if one or more of the extreme locations makes the problem better and/or worse.

Ok, the gearshift was played with. There is really not a lot of play in neutral as one might think.

With the shuttle in F or R the tractor will move slightly when the gearshift is moved to the extreme positions and then stop any movement. It does it more pronounced when cold.

More experimentation has shown that the "grabbing" is done BOTH with the foot clutch and the shuttle shift when used alone. There is a slight delay with the shuttle shift - I assume it is doing its thing - and then a grab as the clutch engages. It is more noticeable in higher gears of course but does it in all gears and in both HI and LOW range.

My newest suspicion is the hydraulic oil. It was changed at 50 hours along with the two filters but Tractor Supply "Premium" hydraulic fluid was used. It worked fine for a while but now this problem. My next step is to do a drain and fill with Kubota UDT and new filters hoping no damage was done.

What think all of you?

 

[red4now]

Did you ever change the oil and filters? If so, was there a difference?

 

[big bubba]

why was tractor supply hyd oil used at 1st change & not udt? convienence or economics? were kubota filters used? good luck

 

[gwdixon]

Red and Big, thanks for asking.

The filters and oil haven't been changed yet. Been too busy with spring jobs and figure at 200 hrs it would be a good benchmark for the change. Ten hours to go.

Genuine Kubota filters were used. TS oil was on sale at a quarter of the price of UDT. The 5 gallon container specifically states that it is equivalent to "Kubota UDT".

Now I have my doubts. Perhaps it is equivalent when new but breaks down quickly. That is why the change back to genuine UDT will be made to see what is what.

In addition, the hydraulic pump seems to "growl" more than usual. Symptoms keep pointing to the oil.

 

[big bubba]

mr dixon: think 200 is a good benchmark, i changed the filters at that interval (having changed them & oil @50)....betcha you'll be up to speed if you change hyd fluid & filter w/original @200. Mxx40's are awesome machines, welcome to the club bb

 

[gwdixon]

The hydraulic oil is changed at 50 hrs and then every 300 hrs according to the manual. The engine oil at 50 hrs and then every 200 hrs. So it would be hour meter reading 350 for hydraulic and 250 for engine.

If everything is done at 200 hrs. as it was at 50 hrs. then my thinking is it is like having a "second break-in period" fluid change.

That is: 50 hrs., then again 150 hrs. later, and then on to the schedule specified in the manual. That may be too cautious but piece of mind is priceless.