Hydraulic noise

[uphere]

Got a hissing sound from my 2740 that I am just starting to hear (old age) - it appears more prevalent when I am using the loader (and going in reverse?) - and appears to disappear when I am turning. Fluid levels are good. I have noticed that the loader will drop a foot overnight though. Any ideas?

 

[oldnslo]

Got a hissing sound from my 2740 that I am just starting to hear (old age) - it appears more prevalent when I am using the loader (and going in reverse?) - and appears to disappear when I am turning. Fluid levels are good. I have noticed that the loader will drop a foot overnight though. Any ideas?

Hissing noise: Does it sound like fluid escaping under pressure? Ie. spraying.

When using the loader is it more pronounced when raising the loader Vs lowering the loader?

Does the loader function properrly? I.e. lift the same load at the same speed as before the noise?

Roy

 

[uphere]

Roy - my thought was fluid leaking but the level is fine and has not moved. Seems it do it when raising and lowering - the loader works fine however I tend it think it lowers a bit more "jerky" than before?

 

[oldnslo]

Uphere,
I was wondering if there is an internal leak in your system that is allowing oil to spray back into the tranny housing. This would give the "hissing noise" but I would expect it to cause the loader to move slower when under load.

Can you see the oil in the tranny after you have run it for a few minutes? Don't drive it around just run the hydraulics. If you can, does it look foamy or full of air bubbles? If it is there a leak some where.

If there are lines inside the tranny one of these could be cracked.

If the system relief valve is in the tranny it could also be jammed partially open from a piece of debris.

Does the 3 point hitch have its own valve external of the tranny housing or is part of the casting? Do you rear remotes where the valves are mounted to the tranny housing. These get oil from some where and could also be leaking.

I am not familiar with how Montana builds there tractors so these are just some thoughts and suggestions on how to possibly start narrowing down when the problem is.

best of luck.

Roy

 

[uphere]

Roy - no foamy at all - (might be a bit more fluid than required though (but not by much). I do notice that only when I curl the loader does the noise goes away?

No leaks!

Relief valve sounds like a interesting idea though?

 

[oldnslo]

Roy - no foamy at all - (might be a bit more fluid than required though (but not by much). I do notice that only when I curl the loader does the noise goes away?

No leaks!

Relief valve sounds like a interesting idea though?

Time for another suggestion. If you very slowly move the lever to curl the bucket does the noise change or stop? Do this very slowly and see if the noise stops and the bucket does NOT move. If this works it sounds like the linkage is not allowing the spool to center properly which would also cause the higher velocity hissing sound.

Can you carefully touch different parts of the plumbing and valve assembly to see if one part is getting hotter than the other? Heat is also an indicator of pressure drop from fluid velocity.

Suggestion are easy to throw out, just have to find the right one.

good luck

Roy