Occasional weird L4150 hydraulic probelm(s)

[kmdigital]

I was using my L4150 Hydraulic shuttle tractor earlier this week, and suddenly it wouldn't move at all when changing directions. After a bit of moving the lever back and forth and increasing the RPMs to about 1500 it slowly started to engage the clutch and suddenly it moved just fine. I had just started it a few minutes earlier, and while it moved fine initially, it suddenly did this.

After using it a few more minutes, where each change of direction was very slow in engaging, it gradually improved (maybe as the oil warmed up?) until it was working normally again. It was about 40 degrees outside, so not very warm, but the tractor was inside where the temperature was probably closer to 55 or so before I started it.

About 2 hours later the 3-point hitch suddenly wouldn't work either! IE: it wouldn't go up, no matter what I did with the control lever. After about a minute of moving the 3-point and draft control levers around, it suddenly started working again, and worked just fine for the rest of the day as well as the next day. Strange!

Anyway, the hydraulic fluid level is fine, but maybe the filter needs to be changed? Strangely enough, both times the loader worked just fine, so I assumed that the hydraulic pump is working properly. If this is the case, it doesn't make much sense that the filter would be clogged, but then again....?

I seem to have heard somewhere that the Hydraulic shuttle on the 4150 can be adjusted to change how it shifts. I assumed that something with this, (and cold oil) may have been the cause of the shifting issues, but I don't see how this could have any affect on the 3-point.

Anyone have any ideas or suggestions as to what mightthe problem might be?

 

[rbargeron]

These symptoms sound like they may or may not be related. It is possible that adding a couple of gallons of trans fluid could cure everything. But maybe not.

A sluggish shuttle can be caused by the clutch pressure dump valve staying open too long, or the pump not delivering enough oil. When the shuttle lever is moved to neutral, the pressure is supposed to drop, but should build again when the lever goes to the other position. If you shift quickly does it work better? (Need to try that at low rpm)

Is the tractor level or inclined when this happens or is that not a factor?

Does your L4150 make a snapping noise when driving along in 7th or 8th ? On 4150's and 3750's the oil got air bubbles at the pickup point due to the gears turning at the oil surface. The snapping is caused by air going through the loader valve's hoses . Kubota offers a fix - lengthening the internal pickup pipe and increasing the oil quantity (they supply a new shorter dipstick for the trans). Lack of 3ph motion is most often oil starvation, so I would try adding 2 gallons of fluid, even if the level seems ok now - and see if the symptoms go away.

You are right - the L4150's shuttle valve has an "orifice selector valve" which compensates for climate/oil viscosity - it can be set for faster or slower shifting. It is located below the instrument cluster - can be seen with a bright light if you take off the plastic around the steering column. Use a hooked wire to reach in and pull or push the lever to another position. It is possible that dirt in the orifice valve is causing a partial restriction.

Do you have the factory manual? On my 5450 the shuttle control valves are external - they are different on the 4150 but still external. It would be nice if it was something simple like bent linkage or debris jambed in somewhere.

As always, prompt cheerful refund if info is bogus /forums/images/graemlins/smile.gif.

Take care, Dick B

 

[kmdigital]

Thanks Dick,

I will need to try moving the shuttle rapidly, although I don't think that made any difference. The tractor was on level ground (relatively) at all times, so this shouldn't have been a problem.

I don't recall any snapping sound, but I don't drive it in high gear very often. Yes, I do have the manual, but haven't taken the time to look at it yet. I didn't think it was likely to give me any specific info regarding these problems anyway.

One thing I forgot to mention, is the remote hydraulics also still worked (loaded the engine), even the the 3-point didn't move for a little bit.

I will check the oil and make sure it is at or above the full line. I supose I should probably change the trans oil and filter, as I don't know the history of its maintenance. The oil looks very clean on the dipstick, but it could have been in there for a while. One thing I do know (I called the dealer) is that it had a new clutch installed about a year before I bought it, but they didn't say anything changing fluids. I don't know if this would be required to change the clutch or not.

Also, since this isn't a hydro, is Super UDT worth the expense, or do I just put in regular hydraulic fluid? Considering that it holds quite a bit of oil, the standard fluid would work just fine for what amounts to a standard transmission.

 

[rbargeron]

It is a gear-type transmission but the hydraulic shuttle plays a very central role - without proper hydraulic pressure there is NO drive in either direction.

The L4150 has a dry clutch for the drive wheels and the pto. To change the clutch disk requires splitting the tractor - which means taking off the external hydraulic pipes - so the fluid would be drained.

Unless you are in an extremely cold location and the tractor lives outdoors, regular fluid is ok. My 5450 has wet clutch and hydro shuttle - no problems in Massachusetts winters - it lives in an unheated barn. My 4150 never had any hydraulic issues here either.

The lazy 3-point-hitch but working remotes is a real head scratcher.

Hope Kubmech sees this and chimes in.

Dick B

 

[rbargeron]

Any update on the hydraulic symptoms?

 

[kmdigital]

No, except it has worked fine the last several times I used it. And I didn't even add more hydraulic fluid. I know it is up to the full line, but I haven't taken the time to overfill it a little, because everything has worked ok since. I don't know what the deal is/was several weeks ago when things just didn't seem to want to work properly.

I hadn't used the tractor for several weeks, but used it for about 2 hours this past week to grade some major potholes out of a driveway, and the shuttle worked promptly and the 3-point worked every time. Strange how one day things act up and later everything works A-ok. Just hope everything continues to work.......

 

[rbargeron]

All righty then ! A problem that fixed itself and went away /forums/images/graemlins/cool.gif Probably just some microscopic traveling crud temporarily lodged in a valve somewhere - may never happen again. The L4150 is a very robust machine - one of Kubota's all-time best in my book. DickB

 

[kmdigital]

As an update to this problem, the other day (while driving down the road) the hydralic filter light came on. Yesterday I decided to change the filter, and barely any oil ran out of the case. A little investigation showed some sort of pieces of gunk (thought it looked like bark at first) were packed at the base of the filter mounting plate. I used my finger to dig them out, and boy did the oil run out then (apparently goes straight to the transmission case).

I cleaned out everything I could reach with my finger, and also pulled the drain plug (which is directly below the filter mounting area) and it barely drained there either. With a little judicious poking and scraping with my finger (fortunately my fingers are fairly thin and long) I got more material out of the drain hole (along with a bunch of oil) /forums/images/graemlins/crazy.gif

Upon examination I found that the blockage was a significant quantity of old flat gasket material. It seems some "mechanic" did a very sloppy job and let the old gasket material (from an earlier repair) fall into the transmission and never bothered to remove it. I know the tractor had a new clutch installed about a year before I got it, so I assume that this is when this happened, although I don't know if a clutch job would actually involve opening the transmission case.

Now the hydraulics work MUCH better then they did before! 3-point is faster, and even the FEL cycles faster. I didn't drain all the fluid, as it looked nice and clean, but I drained enough that I got all the debris out around the drain area. Hopefully all the gasket material had settled in this area by now, so that I won't have to do this again in the future.

Goes to show that even some so called "professional mechanics" do a lousy job. Unfortunately, this is why I normally do all my own work. I have found that I do a much better job then they normally do, I suppose partially because I am not under they gun they way they usually are with flat-rate hours, etc. But there is no excuse for this sloppy work.

 

[rld]

I had similar hydrolic symptoms that cleared up after a new filter. I was told that the gasket like material in the filter was brake material. This is supported by the wierd noises when braking on one side. The brake job I have not tackled yet. New filters are easier for now.

 

[nightowl490]

Welcome to the L4150DT rear brake coming apart club, get about 4 hydraulic filters and 5 gallon bucket of hydro oil. When you light comes on it's debris. Not a big deal and your brakes will continue to work. 500 hours on a well made machine and this works. Good luck