L3400 3-point hitch adjustment

[timberland]

Ok guys this thread has got me inspired to do something about my jerky hitch. My serial # is 57809.
Does mine have the same valve as Chillys'

If not, can anyone tell me which valve i have.

Thanks

 

[Caseyb1]

That's a great point, is the setup the same on all the versions of this valve? Or are the settings different?

Sean, do you know?

 

[Chilly807]

Ok guys this thread has got me inspired to do something about my jerky hitch. My serial # is 57809.
Does mine have the same valve as Chillys'

If not, can anyone tell me which valve i have.

Thanks

A dealer would be better equipped to tell you for sure, but I think you have valve type YR909-00100, which is the older type of valve. Apparently they were much worse for bounce than the newer versions.

I'm guessing your tractor is probably 2005-2006 vintage. I don't think they made that model prior to that.

According to my dealer, he thinks mine has the YR908-00104 valve, going by the serial number.

I got my parts list online a year or two ago, I think it's still current since the L3400 is out of production.

From what I can see, there were maybe 6 different valve versions used. Some are noticeably a different shape (rounded corner in the old versions), and some probably have more subtle internal changes or refinements.

Sean

 

[Chilly807]

That's a great point, is the setup the same on all the versions of this valve? Or are the settings different?

Sean, do you know?

I think the set-up is the same, but I can't say for sure. That's why this is a seat-of-the-pants thing, even going by the WSM which only has one set of adjustments listed, and a release date of August 2008. There may be a reason the valves are set the way they are when they leave the factory that we're not aware of. I'd like to think Kubota's right hand knows what the left is doing, but I'm not 100% sure that's the case.

My only real concern is possible high oil temperature over prolonged use or in hot summer weather. I think the reason the valve is smoother is that some flow is going through it all the time as opposed to it simply being "locked" in neutral before. It's the transitions from "locked" to flow and stopping again that make it so rough, but that's a guess on my part.

Oil isn't going over the relief valve all the time, that much I do know. Very different sound when that happens. The fact that the lift settles a bit when you shut down tells me that the hydraulics are applying pressure to the lift piston to maintain the steady position while the engine is running. When you shut down, that pressure drops, and so does the lift until the feedback lever cuts off the draining of oil and stops the downward motion.

Whether that is going to be harmful or not is the question I have in the back of my mind. I'm going to keep an eye on the oil temperature (going by feel) for a bit and see if it gets noticeably hotter than before. If it does, I'll have to re-think the situation and weigh off benefits and drawbacks.

The hitch is 100% smoother than it ever was, but if it causes other problems that's something that has to be considered.

Not what anybody wanted to hear, I know, but it's what I'm thinking.

Sean

 

[Baby Grand]

<snip>

It seems like there isn't much difference between 0.006" - 0.016" gap, all have very smooth lift with a slight "settle" or "sag" when you shut down. I didn't try anything below that. The spec is for 0.004"-0.008" gap (0.1-0.2mm). Once you go above 0.020" gap things get interesting, however.

I tried going back to the original setting of 0.045 to see what would happen. Sure enough, the jerky action was back, but there was no settling of the hitch when you shut the engine down.

I reduced the setting to 0.030", and something I wasn't expecting happened. The hitch started cycling slowly up and down about an inch all by itself.

Reducing the setting to 0.026" made the cycling much worse, enough to actually shake the tractor with only a drawbar on the hitch arms. About 3-4 inches up and down fairly rapidly.

I tried going down to 0.020" and the hitch was close to being stable, a couple of minor oscillations then it stabilized for the most part. Right on the edge of acceptable, I think. It also settled about an inch after shutdown at this setting.

<snip>

Sean

This is really great information for doing diagnostics! Actual, controlled measurements. Now you can observe the way your hitch is behaving, then refer to this guide and figure out how much adjustment to make on your valve. Awesome.

My hitch doesn't jerk a lot, but when grading with the rear blade it's just enough to really pizz me off. It also doesn't settle at all when I turn it off, so that leads me to think that a small adjustment will smooth out the action to an acceptable amount.

Thanks for posting this!

-Jim

 

[jenrow33]

Chilly,
I have a 2007 year L3400 but I haven't noticed and issues with mine and I think if it were as bad as your "before" video it would be obvious. Do you know if this problem is with gear shift tractors only or HST as well?

Great thread and great information! I have saved the link to my favorites in case I ever need it! I applaud you for taking the time to take photos and post. The good info keeps streaming from TBN.

Internet.....what a great invention. Thanks Al Gore.

 

[LD1]

Chilly,
I have a 2007 year L3400 but I haven't noticed and issues with mine and I think if it were as bad as your "before" video it would be obvious. Do you know if this problem is with gear shift tractors only or HST as well?

Great thread and great information! I have saved the link to my favorites in case I ever need it! I applaud you for taking the time to take photos and post. The good info keeps streaming from TBN.

Internet.....what a great invention. Thanks Al Gore.

It is both gear and HST tractors and goes back till they first started the L2800/3400 models and all valves involved, allthough some better than others.

It is becoming cleared that this is just a case of a mis-adjusted valve and kubota denying any issues.

Mine is either a 05 or 06 model (cant remember) but was bought in feb-2006, and has had the issue since day one. I just ignore it because I dont use the 3PH for anything that requires a super-steady hitch. Just mainly bushhogging and mowing. Which is either full-up or full-down. The jerkyness only is apparent when trying to lift very slowly on the way UP ONLY.

 

[k0ua]

Mine is 2010 Hydro, and it is a spitting image of chilly's "before" video. It has the later model of valve. I wish it looked like his "after" video

James K0UA

 

[sadie72]

Unbelievable! Great work Sean. Thank you.

Do we all feel this is the same issue with the L3800 model? Do they use the same type valve? I just purchased a L3800 which exhibits the same jerky vertical motion at slower lever movement. NOT acceptable for a normally high quality Kubota product. To be frank, I'm tired of hearing from Kubota that I should have bought a Grand L.

Is the adjustment procedure the same for a L3800 as Sean details so nicely on his L3400?

 

[Chilly807]

This is really great information for doing diagnostics! Actual, controlled measurements. Now you can observe the way your hitch is behaving, then refer to this guide and figure out how much adjustment to make on your valve. Awesome.

My hitch doesn't jerk a lot, but when grading with the rear blade it's just enough to really pizz me off. It also doesn't settle at all when I turn it off, so that leads me to think that a small adjustment will smooth out the action to an acceptable amount.

Thanks for posting this!

-Jim

Jim, normally the GL's are really smooth... I have no idea what the inside of your's looks like. I guess it could be the same kind of problem, you'd have to check valve part numbers to see what it has in there.

It's an odd thing.. we have a couple guys with L4400's that have the same problem, a couple of MX5100's, and one M59 of all things :confused2:

Sean