JD 2440 hydraulic squeal

[cbailey1956]

Hello, neighbors 2440 (yes really my neighbors) hydraulics are squealing. When using the rear remotes to operate the loader and or operating the 3pt lift the noise goes away. As soon as hyd pressure is not needed the noise resumes. Steering circuit has no effect on noise (works great). He brought it over after talking to me and saying he had changed a hose and the loader no longer worked. I would say it had a few hours running before he brought it to me. I traced the loader problems to incorrect routing of lines to the two rear remotes. Rerouted and reinstalled lines. Now the loader works fine and has good pressure/pwr. The squeal persists unless operating a circuit. It sounds like a relief valve to me but I dont know where they could be located. I have looked over the tractor and it appears to be a closed circuit radial style pump up front. I am assuming there is a charge pump somewhere internal and hard to get to. There are two large lines running from the rear to the front pump / cooler. 1 pressure line running rear that has a T feeding the steering and going through a small valve assembly prior to suppling the rear remote valve assembly. I plan to drain the fluid and pull what looks like a filter assembly from the bottom. Is there a screen somewhere and are there any valves I can inspect without major disassembly. Oh the tractor has the hyd hi/low selector on the dash. It shifts fine and no noise while changing lever. The pressure line is vibrating/chattering while in operation unless fluid is used to operate remotes / lift. Any hints/advice?
Craig

 

[jd110]

A good place to start is to change the filter and drain the transmission fluid and check the sump screen. Sump screen is located on the right side of the transmission, just behind the filter housing. There is a large plug there that takes a 1/2" drive breaker bar to loosen it. Tap on the plug a couple of times with a hammer to make it easier to come loose. The screen is about 10 or 12 inches long. If there is any debris on the screen, it is important to identify what it is. If it is brake material(tractor has wet brakes) brakes need to be repaired to prevent further contamination and damage to the system. If the noise persists after filter change and screen cleaning, you could have a high pressure internal leak. Can you tell where the squealing is coming from? Do any of the hydraulic components get warm/hot when running? Will the three point stay up with engine off? Does the loader have an independent valve or is it operated from the remotes? What model is the loader? Some of these tractors had a "buzzing" noise from the shift lever area that is somewhat normal. It is irritating, but causes no problems. It is caused by the pressure regulating valve for the Hi-Lo vibrating in the shift cover housing. You probably should also check main hydraulic pressure(2300 psi) and transmission pump pressure (around 140psi). Also, you are correct, the transmission pump acts as the charge pump for the main pump. It is located in the rear of the clutch housing.

 

[cbailey1956]

Thanks for the info. Tomorrow if time permits I will drain and check filter and screen. The loader has no info on it, it is operated with hoses from the rear remotes. I will check main PSI at rear remotes. Where is the transmission psi port? I will raise the 3pt and see if it holds also. Thank you

 

[Tx Jim]

With 3pt raised,engine running look inside hyd filler hole at the rear of tractor for spraying oil. This is a very common hyd leak problem on JD utility tractors. The stroke control valve(parts keys 42,43&44) that controls pressure is in the head of the frt pump. Stand-by should be in the 2250-2350 psi range. The valve on RH side back by hyd filter is the pressure control valve that gives steering priority hyd pressure. If tractor has ind pto(control lever between gearshift levers) there's a trans test port under sheet metal cover the gearshift lever protrude through.

 

[jenkinsph]

In the drawing Jim posted there is also a filter screen (#17) that I would check too.

 

[Tx Jim]

Steve
You're correct and thanks. That filter gets forgotten about.

 

[cbailey1956]

Today I drained the oil, it was clean and no burn smell. Main filter was clean, no debris visible. Screen was about half covered with bits of rubber , only one metal thread like debris. After reading the above info I wanted to pull the filter in the front pump but it was so covered I had to stop and pressure wash which led to fixing the psi washer first. Got it cleaned and will check that filter tomorrow. I wanted to ask about the steering priority flow valve. Can it be taken apart and inspected after removal. I would do front valve/ filter and priority flow valve before reinstalling filters and fluid. Then check pressure and 3pt leak as per above. And yes the tractor does have independent PTO. Thanks for the help so far.

 

[jd110]

Yes the pressure control valve can come apart. You will want to get orings #11, 12, 13, 15, and 20 to reassemble.

 

[cbailey1956]

Took the filter (#17 above) out and it was clean, took the stroke control valve apart and inspected, nothing noticed. Disassembled and inspected steering priority valve, looked good. Checked pressure at rear remote (2700). Took off transmission cover and want to check charge pump psi but found many test ports. 3 on shift plate cover, 3 on lift cover housing, 2 on right side of lift cover forward of the 3 pt lever and 1 on the front edge under the trans cover. all appear to be #3 SAE and I am looking for a test fitting to check pressure. I also looked through the fill port and saw no fluid spraying while the lift in up and also moving. The lift stays in the raised position and holds in respect to the lever position.

I am leaning toward the front pump. While running the pressure line vibrates and the noise appears strongest while listening up front. The loader also appears to be "stuttering" while operating at times. Need to get the charge psi checked but any more suggestions. The noise is more of a rattling rather than whining sound.

 

[Tx Jim]

The noise is more of a rattling rather than whining sound.

First you need to lower stand-by pressure to 2350-2400 psi maximum. Are the hyd line clamps(parts keys #18 & 21) in place and snug?? I've seen tractors with these missing and lines rattle/vibrate. What type valve controls loader???