JD and HST

[_RaT_]

Curious after a post in the HST/Gear comments whether JD requires you to run your HST at full throttle. Does your JD manual require this or mention it. In my test rides on the JD's, I never ran it at full throttle. Partly because I did not need to and partly because it was a new engine and since it was not mine and someday going to be someones, I did not want to in any way damage it. I'm curious as CowboyDoc mentions that you do and it is stated in the manual. I find it odd that JD would require this. Thanks, Rat...

Oh yeah, if it does say this, do you?

 

[cowboydoc]

I never said this and you know it. I said other people have said it. I never mentioned anything about John Deere manuals or hst's.

 

[_RaT_]

From your post
"It's your opinion that you can run your tractor at lower rpms but the manual and other owners disagree. "

Sorry Richard, I took manual as the manual that comes with your tractor not as manual as in gearbox. I wonder why a manual tractor owner would say you have too run your HST tractor at full throttle when they are using a manual. Prior ownership perhaps or just speculation. At any rate, the question still stands.

Do you have to operate your JD HST at full throttle in order for it to work properly or perhaps at all.

Thanks in advance, Rat...

 

[cowboydoc]

Rat there are many people in that thread that said the same thing. I was merely pointing out their interpretation of how an hst is to be operated. I was merely trying to answer your question about misinterpretations. The whole hst argument goes this route every time. Since you've asked it does say to run my JD 455 at full throttle for best performance and it is an hst.

 

[_RaT_]

Silly question, but what is a JD 455. My JD 510 a front deck mower runs at full throttle, it is a gas lawnmower. It runs at full throttle simply beccause that is needed for the blades to cut and develop the lift to get that grass through the chute. It runs fine at less then full throttle when going from point A to point B. The manual tells me to use full throttle when mowing for this very reason. Kind of like my tractor, it uses a 540 PTO that rarely if ever gets that high as the cut is no better at 540 then at 480 to 500 RPM. This means an engine operating speed anywhere from 1800 to 2300 RPM, still well below the 2800 RPM max. On top of that, my peak torque is well below 2000 RPM which works out very well. Rat...

 

[Gary_in_Indiana]

For what it's worth, I have a JD 4200 with HST. I don't recall reading anything in my owner's/operator's manual about running at full throttle for the HST to operate properly. I'm not saying it's not there, mind you. I'm only saying I don't recall anything about it in there.

I can tell you that my HST seems to operate just fine at whatever throttle level I've used. Obviously, it lugs a bit at the lower throttle speeds on some surfaces, but it works. /forums/images/graemlins/smile.gif

 

[shady1701]

I suspect the HST and full throttle is same as my ford hydro i had when you run the engine lower on rpm and use high gear throttling it tends to over heat and cause the rear unit to over heat..

 

[cowboydoc]

455 was replaced by the X series. It's a 22 hp diesel tractor that's used for a number of things from mowing, snow removal, tilling, etc. It has a three point and you can put loaders on them. Mine is used for mowing, snow blowing, tilling and snow plowing.

 

[rockyridgefarm]

from the 4310 manual on HST operation:

<font color="green"> The range shift lever (A) provides three speed ranges.

The range shift lever is used in conjunction with the forward (B) and reverse (C) travel pedals.

IMPORTANT: Avoid damage! Select the proper speed range for the job.

· The machine may be operated with engine speeds at 950 - 2920 rpm. Within these limits, the engine can be placed under varying load operations.

· Never overload engine by lugging machine at low idle speeds.

· Raise engine speed to match expected loads. If a slight increase in engine rpm occurs simultaneously with moving hand throttle lever forward, the engine is not overloaded.

</font>

Nuff said!

 

[GreenMtnMan]

Rat, your question carried the implication that engine speed should be limited on a new JD tractor. Unlike Kubota, JD does not request that you limit engine speed on a new engine. In fact my dealer said crank it up and let it run, just be sure to let it idle for a couple of minutes before shutting it off to prevent heat build-up.

 

[_RaT_]

The Kubota manual says not to run it at full throttle, I guess that running it at 50 RPM below is OK. At any rate, it just did not seem the right thing to do to something I did not own. It does seem that break in procedures have changed considerably over the years as metalurgy and machining have continued to improve. Rat...

 

[JC4HD]

Mike,
Excellent job answering the question... there should be no further misunderstanding of that one! /forums/images/graemlins/wink.gif

 

[rockyridgefarm]

YUP, I made it up all by myself! /forums/images/graemlins/smirk.gif

NOT!

 

[Hambone]

The reason you don't want to idle around with a hst. The oil runs in a loop. There is a secondary pump that resupplies the loop. You have some oil return to tank through internal leakage ect. When not operating at high enough speed the supply pump can't keep up with the demand for the primary hydraulic pump.
I am not saying idling down you're driveway is going to starve and cavitate your hyd pump. But, you have to match engine speed with load to have enough flow.

 

[_RaT_]

Computer genius you are rockyridgefarm, right after John Miller III. Are you trying to say then that perhaps the need to run the tractor at near full throttle does not apply to the JD 4310? /forums/images/graemlins/smirk.gif Just kidding, I understand.

 

[Docsknotinn]

For what its worth it would not suprise me that any manufacturer would say dont run at full speed for the first 50 hours. Thats just the break in. Maybee its just my flawed thinking but dont we all run them near full tilt to get the PTO to speed ? Ok well I never understood the Kubotas that dont have a tach, maybe they have a light or something but they are all up there on the ole rpms. Anyhow, I'm glad thats all ironed out.

 

[rockyridgefarm]

I can NOT make out JMIII's tailights from here.... /forums/images/graemlins/shocked.gif

I did remember the passage I quoted and felt spurred by you to refresh the grey stuff. /forums/images/graemlins/cool.gif

I have benefited greatly from input from you, JMIII and the Doc. And hordes of others.... Thank you very much! /forums/images/graemlins/grin.gif

I, for one, and going to drop my rpm's a little from where I have been. And am still thankful every day for the hst. RaT, Tell your brother in law there's at least one okie that learned from his "experience" /forums/images/graemlins/laugh.gif

 

[_RaT_]

"I, for one, and going to drop my rpm's a little from where I have been. And am still thankful every day for the hst. RaT, Tell your brother in law there's at least one okie that learned from his "experience" "

You remember that!? I have another picture thats even better.

 

[rockyridgefarm]

</font><font color="blue" class="small">( You remember that!? I have another picture thats even better )</font>

Don't tell me its a rolled GREEN tractor...! /forums/images/graemlins/grin.gif