4440 hydraulic problem

[meangreen71]

I got a 4440 quad range. Had a new front hyd pump put in a few years ago. the hyds have never been quite the same since. problem is. all works fine till the oil is warmed up and then hyds seem to slow down. even the steering seems to get alittle harder also. funny part is like when its hooked to a hyd cylinder sometimes it will raise fast like it should and sometimes it raises quite abit slower. the hyd speed control is set as fast as it can go. i have changed filters and they seemed clean even cut them open. sometimes the hyd hoses seem to pulsate when raising. could it be sucking air from somewhere? what do you guys recommend i try next? any help would be apprieciated. thanks. btw the front pump was replaced because the seal around the shaft kept blowing out everytime it was replaced.

 

[rexhellwig]

The best recommendation I can give you is to find someone with factory training on this hydraulic/power train design. {He won't be much younger than 50.} Then you pay him what he is worth. I have a hunch a 1400 dollar pump has already been needlessly replaced.

This pump can only move the oil that is supplied to it. There is a factory engineered procedure for testing the tractor. Guages and possibly even a flow meter with appropriate fittings are needed to diagnose the problem{s} [b:654c4848f0]before [/b:654c4848f0] the tear down. If you have these tools, post back. If your shade tree mechanic has these tools, have him post back. There are enough people here to guide him through anything, but it will take longer on a "message board" type forum.

Or...you can play hit or miss till the cows come home. But consider this; Your symptoms [b:654c4848f0]may [/b:654c4848f0]indicate a problem in the lube circuit. This means you could be putting your clutch and two-speed at risk. $$$$$

 

[powertech84]

sounds like an internal leak. have a good tech do a full hydraulic work up. it could be anything from pto brake piston seals to rockshaft.

 

[mattd]

do all of the scv boxes have low flow out of them? if only one does it then its with that box. what is your stall pressure? trans lube pressure? clutch pressure? if you have an internal leak in your hydraulic circuit then transmission lube pressure will be low and will cause damage over time. one thing im starting to notice is 30 and 40 series are starting to get their second set of rockshaft bushings put in. take a long pry bar and pry between the final drive housing and rockshaft. if there is any movement up and down have the bushings replaced. the reason this is important is there is o-rings around the rockshaft that seal return oil. if these bushings get loose they can tear the o-rings and cause a return to sump leak causing the pulsating. take your tractor to a good dealer and have it diagnosed. most of the time its a cheap o-ring or blown gasket

 

[Tx Jim]

meangreen71,
When you changed hyd filter did you also clean sump screen? I would check stand-by pressure. Factory setting is 2250 psi but 2400 psi is ok and will help speed hyd's a little bit. If this doesn't help then I agree with what others stated.

 

[meangreen71]

Thanks for the information guys. One thing that I forgot to mention is the steering wheel like chatters up and down a tiny little bit also. What would cause that? Like I said all these problems began after the front pump was replaced. A private shop owner installed the front pump. I had let him know right away about the problem and he didnt seem to know what was wrong and kept putting it off. and well of course the pump warrenty ran out so now Im stuck with these problems. Thanks for any help.

 

[meangreen71]

Thanks for the information guys. One thing that I forgot to mention is the steering wheel like chatters up and down a tiny little bit also. What would cause that? Like I said all these problems began after the front pump was replaced. A private shop owner installed the front pump. I had let him know right away about the problem and he didnt seem to know what was wrong and kept putting it off. and well of course the pump warrenty ran out so now Im stuck with these problems. Thanks for any help.