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.