M108s trans/hyd getting hot

[TristarfarmNlawn]

Purchased a new to me kubota m108s with the swing shift transmission also has a side arm mower . Used it today for about 2.5 hrs an noticed the cab floor getting hot, the rear end housing was hot enough to boil my spit. Hyd oil looks good, a little over full. Brakes not dragging, rolls good to a stop. Radiator and coolers are good an clean. The boom mower is not tied into the tractor it is a self contained unit. Tractor seems to run good, shift good etc. Anyone had trouble in the area before. Thanks

Unhooked the draft control linkage thinking it might be holding the lift arms up, lift arms are stuck up. Ran for a hr after an started getting hot again.

 

[Tx Jim]

Welcome to OTT
Which trans does this tractor have(16 or 32 sp)? Hyd oil heating could be caused from internal leak on hyd control relief valve such as 3pt,scv or possible trans relief valve. It's possible feedback linkage on 3 pt hitch requires adjustment. Are 3 pt lift arms stuck in a completely 100% raised position?

 

[SidecarFlip]

Sounds to me like the hydraulic pump is deadheading. Something is connected wrong.

 

[TristarfarmNlawn]

Welcome to OTT
Which trans does this tractor have(16 or 32 sp)? Hyd oil heating could be caused from internal leak on hyd control relief valve such as 3pt,scv or possible trans relief valve. It's possible feedback linkage on 3 pt hitch requires adjustment. Are 3 pt lift arms stuck in a completely 100% raised position?

32sp. Trans. How do I eliminate any of these possible causes? 3pt arms are at 100% I'm guessing, what is the feedback linkage? Is that different from the draft control?
Although this tractor is new to me, it sounds like fluid is trying to work/go somewhere standing at the rear of the tractor.

 

[Russell King]

The feedback rod is connected at the small lift arms and is usually has tab on the front end connected by a threaded rod and nut. On mine it is on the left side near the bottom of the seat. It tells the lift system where the arms are positioned.

Make sure it is attached at both ends
Try to get the arms to move down
Be sure that the lowering speed knob is set to be the fastest lowering speed which should be the direction away from lock position. Turn it many times in that direction

 

[Tx Jim]

I suggest for you to acquire/study the tech manual for your tractor. I checked Kubota parts schematic & I didn't locate a 3 pt feedback rod mechanism similar to my M7040. Several yrs ago I had to adjust my M7040 feedback rod because with 3 pt fully raised the 3 pt relief valve was being opened causing scv to be inoperable.

I agree with Russel that 3 pt not lowering on your tractor needs to be corrected.
My WAG without the aid of a tech manual(WSM) is your tractors hyd oil heating problem is associated with the linkage in photo below. I think the linkage in photo is concealed under rockshaft housing.

 

[freewheel3]

Try lowering your 3 pt. lever a little bit. I know on my MX5000 I can hear the pump bypassing if I pull the lever all the way back to the uppermost position. I just move it ahead an 1/8th of an inch and it's good.

 

[TristarfarmNlawn]

I suggest for you to acquire/study the tech manual for your tractor. I checked Kubota parts schematic & I didn't locate a 3 pt feedback rod mechanism similar to my M7040. Several yrs ago I had to adjust my M7040 feedback rod because with 3 pt fully raised the 3 pt relief valve was being opened causing scv to be inoperable.

I agree with Russel that 3 pt not lowering on your tractor needs to be corrected.
My WAG without the aid of a tech manual(WSM) is your tractors hyd oil heating problem is associated with the linkage in photo below. I think the linkage in photo is concealed under rockshaft housing. View attachment 52612

Located "050" bolt through a plug in the top of the rear end adjusted in all the way off of "080" then took a bar an moved "080" all the way in the back position an made no difference (thinking I would hear it kick in a relief or not). Still sounding like fluid pressure all the time. I'm curious if the arms are just "stuck" an something else may be running. I also hooked up the aux hyd an they seems to work properly.

 

[TristarfarmNlawn]

I suggest for you to acquire/study the tech manual for your tractor. I checked Kubota parts schematic & I didn't locate a 3 pt feedback rod mechanism similar to my M7040. Several yrs ago I had to adjust my M7040 feedback rod because with 3 pt fully raised the 3 pt relief valve was being opened causing scv to be inoperable.

I agree with Russel that 3 pt not lowering on your tractor needs to be corrected.
My WAG without the aid of a tech manual(WSM) is your tractors hyd oil heating problem is associated with the linkage in photo below. I think the linkage in photo is concealed under rockshaft housing. View attachment 52612

Update, believe I have a problem with my pto clutch brake. Turn on pto an everything works and runs cool.

 

[lugbolt]

if you have a WSM study the hydraulic circuit that the pto clutch is in. I am thinking a possibility of something beyond the pto clutch holding up pressure. Meaning, when you turn the pto on, oil is diverted to the clutch when the pto is off that oil has to go....somewhere....back to sump? To another component? Through tube(s) that may be bent/mashed?

 

[Tx Jim]

Update, believe I have a problem with my pto clutch brake. Turn on pto an everything works and runs cool.

Congratulations: Sounds as if you are making progress "diagnosing" your tractors hyd oil heating problem. I agree with Lugbolt that you need to study internal hyd oil circuitry but it sounds as if seal on pto brake circuit has failed

 

[jonfly673]

I know this is late to the convo but I am interested to know what you found out. I am having the same issue with Overheat. My 108s will run for an hour and go into a Limited RPM of around 1500 (while bush hogging). All other HYD and engine indications are good and runs good. I can use PTO and all gears just limited to 1500 rpm. The temp indicator for the engine also comes on and suspect this is an internal engine protection mode. Any thoughts?