Broke Hydrostat twice? Why?

[Bob Christensen]

While working today (with rest breaks for both me and the tractor) I noticed something disturbing.

I have a frame mounted backhoe. It is usually not attached. There is a lever that comes out from under the front of my seat that operates the rear remotes. The lever moves either way sideways and has a detent position at its full travel point. It is possible when entering or leaving the tractor to brush up against the lever and if you do it hard enough, it will stay at its full side detent position. I've noticed this before and I just re center the lever. There is no strange sound or any thing.

But now I'm more alert for any thing odd. How often have I NOT noticed this? There is no telling.

So I tried something. While traveling down the driveway at 2200 RPM, I moved the lever over to full detent. Tractor immediately bogged down by about 200 rpm. No hydro noise. No relief valve noise. No change at all except losing 200 RPM. Since the lever can only be accidentally moved while entering or exiting the tractor, I would never notice the missing RPMs. I would just start it and adjust the throttle.

More and more I'm thinking this is an overheat thing. Sometimes too low RPMs, sometimes the wrong gear, sometimes dirty oil cooler, no temp guage, and now this.

MHE's very helpful post - particularly those graphs - tell me that it is possible to ruin a hydro over a fairly long time without burning or even dis coloring the oil.

Well, tomorrow Jordan is going to mail me the old hydro and my wife and I are going to drive it down to DKrug as soon as we can schedule it, and then we'll all know.

 

[Sysop]

That lever is sending hydraulic flow to the rear ports the backhoe attaches to. With nothing on those ports it "dead-ends" and sends the system into hydraulic relief. While this shouldn't cause any damages short term, it could mess up the pump or the relief system over time. I don't think this is what caused your HST issues.

 

[crazyal]

Just curious, did your dealer put synthetic hydro oil in after changing the HST unit? If not I think it would be a good investment as it should handle the heat better. Another option might be to change the oil out more frequently. You could send a sample out to have it analyzed to see if it's time to change it or just do it at 200 or even 100 hours of use (if you don't want to use synthetic).

 

[buickanddeere]

That lever is sending hydraulic flow to the rear ports the backhoe attaches to. With nothing on those ports it "dead-ends" and sends the system into hydraulic relief. While this shouldn't cause any damages short term, it could mess up the pump or the relief system over time. I don't think this is what caused your HST issues.

Properly plumbed and valved the hydraulic system should not be dead-heading against the relief valve. Is there an open center and closed center mixup ?

 

[Bob Christensen]

Just curious, did your dealer put synthetic hydro oil in after changing the HST unit? If not I think it would be a good investment as it should handle the heat better. Another option might be to change the oil out more frequently. You could send a sample out to have it analyzed to see if it's time to change it or just do it at 200 or even 100 hours of use (if you don't want to use synthetic).

I asked him that and the answer was 'no'.
I didn't discuss that cause I've noticed that disagreeing with somebody about that is akin to arguing with them about religion.

I am a believer in synthetic.

Every car, boat or anything else I've owned for the last 30 years or so gets syn.

Except the tractor. I've been using Kubota super whatever believing it was synthetic, but I find it's not.

I may switch to Amsoil.

In any event, I plan to change the oil after 50 hours like a new tractor.

Look here folks. I know I don' come across here as very smart, but I still drive the Honda civic we bought new 30 years ago. Changed the clutch last year - the first non maintenance dollar ever spent on it. Probably because I taught four consecutive nieces how to drive stick on it.

But I did'nt grow up around tractors. All my knowledge has come from you. That and trial and error of course.

Actually I' amazed how polite everyone's been to me here. This is the internet after all.

 

[Bob Christensen]

Properly plumbed and valved the hydraulic system should not be dead-heading against the relief valve. Is there an open center and closed center mixup ?

I'm not sure what that means, but I don't hear a relief valve opening.

 

[buickanddeere]

I asked him that and the answer was 'no'.
I didn't discuss that cause I've noticed that disagreeing with somebody about that is akin to arguing with them about religion.

I am a believer in synthetic.

Every car, boat or anything else I've owned for the last 30 years or so gets syn.

Except the tractor. I've been using Kubota super whatever believing it was synthetic, but I find it's not.

I may switch to Amsoil.

In any event, I plan to change the oil after 50 hours like a new tractor.

Look here folks. I know I don' come across here as very smart, but I still drive the Honda civic we bought new 30 years ago. Changed the clutch last year - the first non maintenance dollar ever spent on it. Probably because I taught four consecutive nieces how to drive stick on it.

But I did'nt grow up around tractors. All my knowledge has come from you. That and trial and error of course.

Actually I' amazed how polite everyone's been to me here. This is the internet after all.

Apparently Washington State doesn't salt the roads in winter ?

 

[Coyote machine]

Bob, I call BS on the you're not very smart thing. Unless you stop self deprecating we'll have to send some old geezer TBNers, who are almost out to pasture anyway, out to Washington to set you straight!:laughing:

You're learning, as most of us do by talking about our machines.
Your backhoe lever/fluid flow might have been contributing to your trans failures; I can't say for certain because I'm not familiar with your hydraulics and I'm not an expert in this field.

Can you modify the lever so you can't accidentally drop into the detent unknowingly? Other idea would be to post a note near the key as a prestart checklist for the 'pilot', you. This would remind you every time you go to start what needs to be checked before takeoff.

Synthetic oils: I have used Amsoil for my Kioti engine, but not the HST. In fact, I've never changed any HST fluid in over 750 hours since new. It's sort of an experiment, because my dealer doesn't change trans fluid unless it shows signs of water or other contaminants.
I do plan to change it fairly soon, with Kioti's own branded HST fluid, so as to cover all the bases, might as well use the recommended fluids.

Running synthetic, or a blend, as an alternative to dino in your HST ought to give you some edge, but make sure it meets wet brake and any other required content specs that the current dino based oil does for your HST needs.


As far as synthetic for the engine, I've gone to Mobil diesel oil in 5-40 mix for the climate here in VT.

This thread is beneficial to all who want to know more about their HST transmissions, regardless of brand.:thumbsup:

 

[Bob Christensen]

Bob, I call BS on the you're not very smart thing. Unless you stop self deprecating we'll have to send some old geezer TBNers, who are almost out to pasture anyway, out to Washington to set you straight!:laughing:

You're learning, as most of us do by talking about our machines.
Your backhoe lever/fluid flow might have been contributing to your trans failures; I can't say for certain because I'm not familiar with your hydraulics and I'm not an expert in this field.

Can you modify the lever so you can't accidentally drop into the detent unknowingly? Other idea would be to post a note near the key as a prestart checklist for the 'pilot', you. This would remind you every time you go to start what needs to be checked before takeoff.

Synthetic oils: I have used Amsoil for my Kioti engine, but not the HST. In fact, I've never changed any HST fluid in over 750 hours since new. It's sort of an experiment, because my dealer doesn't change trans fluid unless it shows signs of water or other contaminants.
I do plan to change it fairly soon, with Kioti's own branded HST fluid, so as to cover all the bases, might as well use the recommended fluids.

Running synthetic, or a blend, as an alternative to dino in your HST ought to give you some edge, but make sure it meets wet brake and any other required content specs that the current dino based oil does for your HST needs.


As far as synthetic for the engine, I've gone to Mobil diesel oil in 5-40 mix for the climate here in VT.

This thread is beneficial to all who want to know more about their HST transmissions, regardless of brand.:thumbsup:

Well, thanks for your kind words. Any TBNers are more than welcome here. I never have had any friends who had a tractor and I never even sat in one before I bought this one. So I guess it could have been worse.

Yes, I have thought of a way to keep the lever in place.
I think that if I ever did let the tractor run for long with the lever on, it must have at least contributed to heat because those 200 RPMs went somewhere and it seems to me they must have been converted into heat in the hst.

I believe synthetic oil resists molecular breakdown better than Dino oil and I think that it thins out less with heat, but not by much.

I do hope that others do get some benefit from the sage comments here.

 

[Bob Christensen]

Bob, I call BS on the you're not very smart thing. Unless you stop self deprecating we'll have to send some old geezer TBNers, who are almost out to pasture anyway, out to Washington to set you straight!:laughing:

You're learning, as most of us do by talking about our machines.
Your backhoe lever/fluid flow might have been contributing to your trans failures; I can't say for certain because I'm not familiar with your hydraulics and I'm not an expert in this field.

Can you modify the lever so you can't accidentally drop into the detent unknowingly? Other idea would be to post a note near the key as a prestart checklist for the 'pilot', you. This would remind you every time you go to start what needs to be checked before takeoff.

Synthetic oils: I have used Amsoil for my Kioti engine, but not the HST. In fact, I've never changed any HST fluid in over 750 hours since new. It's sort of an experiment, because my dealer doesn't change trans fluid unless it shows signs of water or other contaminants.
I do plan to change it fairly soon, with Kioti's own branded HST fluid, so as to cover all the bases, might as well use the recommended fluids.

Running synthetic, or a blend, as an alternative to dino in your HST ought to give you some edge, but make sure it meets wet brake and any other required content specs that the current dino based oil does for your HST needs.


As far as synthetic for the engine, I've gone to Mobil diesel oil in 5-40 mix for the climate here in VT.

This thread is beneficial to all who want to know more about their HST transmissions, regardless of brand.:thumbsup:

Well, thanks for your kind words. Any TBNers are more than welcome here. I never have had any friends who had a tractor and I never even sat in one before I bought this one. So I guess it could have been worse.

Yes, I have thought of a way to keep the lever in place.
I think that if I ever did let the tractor run for long with the lever on, it must have at least contributed to heat because those 200 RPMs went somewhere and it seems to me they must have been converted into heat in the hst.

I believe synthetic oil resists molecular breakdown better than Dino oil and I think that it thins out less with heat, but not by much.

I do hope that others do get some benefit from the sage comments here.