Tractor hydraulic noise in lines

Well, am not sure the best way to describe what's going on with my 1992 2755 cab tractor 2wd.
So pictures always help.

This has been going on and slowly getting worse over the last 5 years or more, it's time to find out what could be the problem and how best to get it fixed.

I have talked to a dealer and have not had good experiences with them getting these older tractors fixed right the first time.

I have also talked to 3 different independents and none of them seem interested in doing the work or even making any tests... I guess these Mannheim built tractors are rather intimidate them..so I need some input on the best way to proceed.

There has to be somebody in this USA that knows these inside and out, and I would love to find that person....

The noise is in this line and manifests itself when you move the steering right and left only a little bit. Used to only make the noise at low idle speeds but has gone to the point where it's happening all the time once the oil is warmed up.







Only other signs I have had over the last few years is the pto might shut down if I go up a hill at slow engine speed, and the 3 point my shudder if I raise it with a load at slow engine speed.

I last changed oil and filter and cleaned the screen out at 600 hrs ago and it needs done again now. I have never found anything in the screen or oil to this date.

Have never detected any noticeable increase in oil temperature.

Any help or questions I will jump threw fire to get this repaired correctly. I do have the JD shop manual for this tractor TN4434 and it is of no help as far as running any pressure tests or flow rate tests.

Have you ever checked stand-by pressure? It should be 2250 psi.

There are thousands of that and similar models in use, I don't see why any competent mechanic would not be willing to tackle it; after all, the hydraulic system is not that complex.
Having said that, I too have noticed such hydraulic noises in both my 2755 and 2955, but they haven't gotten any worse over the years. It would seem your pump is not getting enough oil or not putting up enough pressure at low RPMs. Are ther any restrictions in the line you pointed out? Having pump pressure checked would be the first step, and if necessary, replacing the pump is not that big of a job.
Ben

I have no answer to your question. I made a cab for my kawasaki mule. The cab seems to
trap the engine noise to a point you want to use ear protection. Nothing wrong with
mule, it's the cab. Same thing with my terramite. I enclosed the top roll cage. It
made the hydraulic torque motor many times louder. It sounds like you are inside a
drum. Then I totally enclosed the rest and now the noise is so bad I wear ear
protection.

I'm thinking it like putting a tuning fork on a piece of wood, the wood vibrates and
makes the tuning fork louder. I think it's called forced vibrations. See if leaving
your cab doors open helps. There may be nothing to do. However you said you are having
other issues with tractor. Perhaps you have air in hyd system, try bleeding it. When I
had hydraulic pump issues on my Jubilee, it had air in lines, made a sound. Good luck.

It might be unrelated, but my 4020 pump is getting VERY tired. Everything drifts down when it sits. When you fire it up and
the pump kicks in the three point arms raise chattering like nothing like you have seen. You can hear them rattling all across
the farm. That was my first thought.

I would get someone on the steering wheel to turn it and setup the noise for you. It may be as simple as your lines vibrating against each other. Its approaching 30 years old.

I have seen more than one set of lines vibrating/humming over the years. Most cases I reinsulate with old vacuum or heater hose.

There are a number of things that might cause such a noise. First, let me say that your symptom is that of a weak pump or low pressure. By nature, hydraulic pumps tend to be noisy - vane pumps more so than gear pumps.
Scoring on the pump surfaces can cause noises. Scoring allows minute amounts of air or oil vapor to be brought in to the compression area. These bubbles collapse and cause what is called cavitation. A weak spring in the relief valve can also cause noise. A weak spring allows too much volume to pass through the pump causing a louder than normal noise.
You said that there were some issues in the 3-point at times. That indicates that the pump could also be starving for oil. If there is any kind of inlet filter, that could also be causing a restriction that might under some conditions cause the pump to starve for oil.
Also, a slight relocation of the lines to keep them from touching each other or anything else might help. There is also the possibility that the noise is the result of a harmonic vibration coming from another part of the system.
My gut feeling is that the pump is worn causing the noise.

Well if your PTO is quitting when you go up hill your losing charge pressure. By not fixing it when it first started doing it you more than likely have problems in the main pump now. The trouble is the main hydraulic pump is striving for hydraulic oil. The shutter your hearing is the main pump chattering from lack of oil on the suction side. The start was just at idle now as it is worse it is all of the time. The PTO hydraulic clutch is ran off of charge pump pressure. So if the PTO lines/hydraulic lines are broken/cracked then your losing charge pressure. It could be the orings in the control valve but it is not likely as the lines are a known failure area. The shutter/chattering will ruin the valves on the back of the pistons in the main hydraulic pump.

To really know you need to check the charge pump pressure. I don't remember what the pressure should be exactly. IRC it is around 150-175 PSI. Guys down on the JD board would remember the exact number. I have not been inside a Mannheim designed tractor in years. They can be a PAIN to fix the hydraulics on. Especially if they are ran with issues. The troubles can spread through the entire system.

The first issue is more than likely the internal hydraulic lines inside the front of the transmission housing. This would be right under the gear shifters. It requires a split at the back of the clutch housing. You can check them by removing the gear shifter housing from the top if the transmission.

You will need to find a mechanic that is familiar with the pre 6000 series Mannheim tractor hydraulics. That is getting harder to do as the older guys retire. Not many younger fellows will have the knowledge to do the repairs in a timely fashion. These tractors can be hard to fix the first, or even the second time. The system is not technically complicated but they always seemed to be more delicate than the Waterloo system. An example of this would be brake linings failure on these tractors would send metal through the entire system. I do mean the entire system, steering valve to the SCV valve, and three point. How it gets by the filters I never could figure out.

So QUIT USING IT!!!!! RIGHT NOW!!!! The longer you run it the more your going to spend to fix it. I hope your PTO clutch is not smoked now. You have been running it with low pressure so it can slip under load easily.

Also your manual is the fix and repair one if it does not have the test in it. You need the other manual: 2155 to 3255 Tractors Operation and Test TM4436S $50

I agree with JD seller that you need check trans pump pressure which should be IIRC 165 psi.

Since you stated pto shut down "at slow engine speed" I'm not that concerned about trans pump output being the culprit.

Another common problem place on JD utility tractors of that era is leaking rockshaft control valves. With 3 pt raised engine running look in hyd filler hole for spraying hyd oil.

jimg.allentown: The JD system on a 2755 has TWO pumps. The charge/transmission pump in the rear of the tractor. It runs at low pressure and pushes the oil to the variable displacement piston pump in the front of the tractor. He has a leak in the system that is either in the high pressure side and the charge pump can't keep up at idle or the more common problem is a leak in the low pressure hydraulic circuit. Which still starves the main pump for oil.

Make sure you start it with the clutch OUT so the transmission pump can charge, and leave it out for a little while before using it.

2755 trans pump will be driven from a different shaft(parts key 12) than the trans input shaft. This different shaft turns anytime that the engine flywheel is turning IE has nothing to do with traction clutch

Those foreign built tractors always have crazy problems,sounds like a problem my Neighbor's Belarus had.

I have a 2550 and it had the same problem. I took it to the dealer and they found it to be an internal leak from the hyd hi/lo.

I took it to the dealer, because they can pressure test and narrow down, where it's loosing pressure

(quoted from post at 15:31:37 04/05/15) Those foreign built tractors always have crazy problems,sounds like a problem my Neighbor's Belarus had.

Click to expand...

I think a JD 2755 is a better tractor than a Belarus.