Hydraulic jerk

[prophet455]

For starters I have an M7040 with shuttle shift. I have noticed that when cold the tractor running in neutral will jerk back and forth. It seems to be the hydralic pump until it warms up moving teh tractor. It jerks worse with the tractor in gear but of course the shuttle still in neutral. Pulls fine and runs fine, but it is a little spooky to watch the tractor running in the garage shifting back and forth a inch or so. Is this normal?

 

[leonz]

For starters I have an M7040 with shuttle shift.

I have noticed that when cold the tractor running in neutral will jerk back and forth.

It seems to be the hydraulic pump until it warms up moving the tractor. It jerks worse with the tractor in gear but of course the shuttle still in neutral.

Pulls fine and runs fine, but it is a little spooky to watch the tractor running in the garage shifting back and forth a inch or so. Is this normal?

--------------------------------------------------------------------------Is the brake set for the rear brakes?

Does the directional foot pedal have a grease fitting? it may need a squirt- also A while back one of the memeber said the oil assist shock might be bad referring to another posting about the same or nearly the same thing.

With cold oil it will surge until it reaches operating temeperature as it is very dense-with a very high viscosity from the cold.

Running a salamander for twenty minutes or so will heat up the reservoir easily for you. Just do not get to close-no burning paint

 

[prophet455]

Sorry but I was not clear. It is not in gear, it is not driving at all that it is rocking in place while running. In gear it is worse but keep in mind the shuttle shift is still in neutral. When you put it in forwad or reverse it drives perfect, it just has a forceful rocking back and forth while in neutral when it is cold.

 

[leonz]

Sorry but I was not clear. It is not in gear, it is not driving at all that it is rocking in place while running. In gear it is worse but keep in mind the shuttle shift is still in neutral. When you put it in forward or reverse it drives perfect, it just has a forceful rocking back and forth while in neutral when it is cold.

It is very cold-I would see how tight the parking brake is and take it up only if needed. If the rear tire are low on air that will add to the rocking too.

Don't forget that shiny orange beast of burden is a huge heat sink too it will absorb a huge amount of cold temperature simply due to its mass. and when it is hot and shut down the heat will leave the tractor quickly and become very, very cold.

How low is the idle set on the tractor? It should no rock any at all but a diesel with a big crank expends a lot of energy/motive force at a very low idle especially when cold combine that with cold engine coolant, cold engine oil, cold hydraulic oil and cold transmission oil and it will buck.


20 minutes with a kerosene salamander and a block heater work wonders but check the parking brake and the rear tire pressures.

 

[prophet455]

it was running about 1700 rpm at the time warming up. Parking brake was not set, just running so the temp could come up.

 

[leonz]

Yes you do need a salamander to the up the tractor.

 

[Yankee Clipper]

Prophet,

You do not say where you live but if your ambient is less than 32 F you should consider using Super UDT in the transmission. Yes, it does cost more but it has a pour point depressant that keeps things fluid down to minus 52 F - if I remember right.

The creeping is caused by the residual fluid in the wet pack not fully stripping off the plates and it wants to try and move. The Super UDT should eliminate this behavior entirely.

Good luck!

 

[prophet455]

Thanks I am in Kentucky and the temp was around 40 at the time. I am getting close to my 50 hour change. I have no real idea what is in the tractor now but UDT would not suprise me. I do plan to go SUDT.

 

[Deerlope]

I have a m-5040 and it does not do that. You need to get that checked out right away. We are also a lot colder here.

 

[prophet455]

so far i am told by the dealer to let it go for a while. Basically they dont know what could be wrong either but they are hoping it goes away (especially with the 50 hour change coming up). It is clearly connected to the hydraulic oil being cold. I have further found out it does not do it at 2000+ rpms nor at an idle, just in that 14-1700 range for 20 or 30 minutes. Also much worse in first or second gear. some in neutral and when it 3 or 4 it is hardly noticable at all. Right now my gut says the clutch plates are dragging in the thick oil. Second guess would be the modulator valve is ... well just "not right". This weekend she is going to get worked again so Ill see if it is better or worse after a day of work. I have seen absolute zero effects during operation. In fact it still seems to go away after the hydraulic oil warms up.

 

[prophet455]

any mechanics that can give a conformation that the wet clutch can drag under cold fluid like this? If not can someone give me a little more detail on teh function of the modulator valve and is this a realistic path to explore?

 

[rancher93]

Any resolution to this problem?
My M5040 just started doing the identical rocking back and forth in neutral as described. Even with the foot clutch pedal fully depressed the tractor rocks back and forth in neutral. My tractor has only 250 hours on it and uses SUDT.

 

[ttowne66]

so far i am told by the dealer to let it go for a while. Basically they dont know what could be wrong either but they are hoping it goes away (especially with the 50 hour change coming up). It is clearly connected to the hydraulic oil being cold. I have further found out it does not do it at 2000+ rpms nor at an idle, just in that 14-1700 range for 20 or 30 minutes. Also much worse in first or second gear. some in neutral and when it 3 or 4 it is hardly noticable at all. Right now my gut says the clutch plates are dragging in the thick oil. Second guess would be the modulator valve is ... well just "not right". This weekend she is going to get worked again so Ill see if it is better or worse after a day of work. I have seen absolute zero effects during operation. In fact it still seems to go away after the hydraulic oil warms up.

Prophet

Gotta love these dealers. Plug ears, Cover eyes and hope the problem goes away on its own. That is awesome information and help! What a joke.