Hydrostatic (HST) Transmission Longevity?

[Darren]

I wouldn't apologize. For once I didn't have to squint.

 

[Bob_Skurka]

Cowboydoc: I am not sure what you are agreeing with. You seem to indicate power loss to HST, and nobody will argue that, but what does that have to do with reliability and lifespan? I think you missed something and might want to reread the original post.

FlDave: I did realize that while I do not own a tractor with HST drive that has 1500 hours on it, I do have a propane fork truck that is driven by hydraulics. It is from the early 80's, gets run 2 shifts a day, 5 days a week. We've rebuilt the engine about 5 years ago, but the drive system is, to the best of my knowledge original. That unit must have 5000???+ hours on it.

 

[_RaT_]

Bob, I'm glad I was not the only one confused.

 

[MikePA]

Anyone who unilaterally dismisses tractors with HST, without asking how you plan on using the tractor is (1) Misinformed or (2) A troll.

If a dealer say this, particularly one who doesn't sell them, is either misinformed or (2) Lieing. In either case, buy your tractor someplace else.

A Search of TBN will reveal there have been dozens of threads about gear vs HST.

They each have their place and are a function of what you want to do with the tractor.

 

[neilly2]

I think like most every question related to what tractor or features to buy, it boils down to what you plan on doing. As you can see most of the opinions are based on what people have and what work they are doing.

I think we can all agree for light to medium use the HST is plenty reliable for a property owner. If you're set on a JD, I reccomend finding a manufacturer's rep. or get a hold of a technical rep. for JD. Usually the technical reps. don't care at all about being salesmen and will give you the straight poop.

I first bought and still own a gear tranny. I actually feel it is safer to learn on, since you think out each move when you're learning the controls. When on an HST I tend to be a little lax in the safety and thinking ahead department (hit it and go). Now, shifting gears is not a thought and when mowing, raking, blading, tilling or hogging I wouldn't consider the HST a big step up in convenience.

BUT, when it comes time to need a loader for a continuous stretch, I have my brother come down with a shuttle shift. Even the shuttle shift gets bothersome after a while, and I would kill for an HST.

Large construction equipment has been running HST for many years. I have to imagine that the HST is more maintenance than a geared tran, but these are production machines and need the speed of HST to make money. The additional cost of maintenance is offset by production. Not the case with most of our 'backyard' tractors.

The John Deere website has 'question email' page on it. Start asking there and keep pushing until you get a good answer. I would be curious to see what they say.

 

[cowboydoc]

I guess I didn't finish what I meant clear enough. PERSONALLY and from MY experience I don't think a hydro would hold up the same as a gear tractor. Do I know of hydros with less than 1500 hours that have failed? Yes. Do I know of problems with gear tractors before 1500 hours? Yes. But I know of more hydro problems than I've ever seen gear problems. That's why I won't buy the 4720. For what I do with MY tractor I have no doubt in MY mind that I would not get a very useful life out of a hydro. I agree with Mike and a few others that have said you need to analyze what is right for you and make the decision about which to buy. For medium and light duty work I have no doubt the hydro would be fine. For what I do with one I wouldn't have one and I don't think it would hold up. That's my opinion and I know nobody will agree with me but nobody else here that I know of trys to farm like I do with one. My needs are different and what I expect of a tractor is different. It's just my opinion based on my experience like all the people that swear by a hydro. No more no less. Doesn't mean I'm right or I'm wrong or vice versa.

 

[Darren]

Doc,

With your situation, you're obviously in a different category as far as requirements. It's up to the individual to evaluate their needs and choose accordingly. There's certainly plenty of infoon TBN to make a decision

 

[Alan L.]

HST results in some HP loss, but not necessarily the "amount of work" that is accomplished.

I have never seen any documented evidence that an HST will last either longer or not as long as gear. Maybe someone can produce a study?

 

[Cliff_Johns]

Here is a brief article on work being done at MU to extend the average life of HST transmissions beyond the average 5,000 hours. The article says that the problem is in the bearings which wear out after about 5,000 hours.

HST research at MU

Cliff

 

[RonR]

Gee, I guess if my hydro bearings go out at about 5000 hours, I won't complain too much. By that time, I should be about 190 years old, and won't remember too much about this Kubota then anyway...........

Have a good one,
Ron

 

[_RaT_]

"HST results in some HP loss, but not necessarily the "amount of work" that is accomplished"

Alan, you bring up a great point. I would often argue that my productivity is enhanced with my HST L3830 versus my gear drive 8/4 International. The many varied tasks I find myself doing each week/month lend themselves very well to HST. In these instances, I would gladly sacrifice a couple of PTO HP for the pure amount of work I can accomplish with HST. My two mowers are not sized for my current tractor. I have a 84" finnish mower and a 80" offset brush mower. The maximum according to my manual is 72". My little L3830 can spin the mowers with ease even in the tall stuff. If pulling a set of rippers in the ground day in and day out was my typical tractor useage, I think I would opt for a shuttle drive and probably not a compact.

 

[OrangeGuy]

Gary in Indiana,

Thanks for the tip!

OrangeGuy

 

[JerryG]

<font color="blue">I know nobody will agree with me but nobody else here that I know of trys to farm like I do with one.</font>
I agree with you, because I don't think that a HST would hold up for what I do either.

 

[_RaT_]

"I know several equipment mfg. that always ask me if I have a hydro or a gear tractor when sizing implements. Most of them say that the hydro will not do the same work with an implement that a gear tractor will. "

Makes me curious now about what implements we are talking about. PTO driven and /or ground engaging? What manufactuers?

 

[Henro]

Too bad this is not an HST tractor... /forums/images/graemlins/tongue.gif

About a year ago B2400 posted the following:

Don't let the hours bother you too much. The prison where I work has a 1986 L2850 2wd that has over 20,000 hrs on it and the only repairs have been three alternators, several(!!) sets of tires, and 1 clutch( courtesy of a bone headed inmate). It is stored in a heated building and receives regular maintenance. This tractor was the biggest selling point for a kubota to me when I bought my first one and have never looked back!!

I remembered the post and previous mention of this tractor with high hours...

20,000 hours...gear tranny...any tranny...pretty impressive...

When it is all over, for the average owner, I can't help but think that transmission type is a moot point today...

 

[To20Chris]

The power that's lost to the drive wheels (greater than the PTO power loss) ends up as heat in the HST hydraulic system. While undesirable, that does not necessarily mean that the reliability is reduced. If the system is designed to eliminate that extra heat, and all the components stay within their acceptable temperature ranges, then there is no real reason it would be. If you are doing serious ground engaging work, or anything where you are putting a lot of power through the drive wheels in a constant way, then such a system would not make the most sense. You’d just be turning diesel into heat for no reason.

 

[RichNJKubota]

Good and to-the-point article on HST longevity problems.
I doubt I'll ever hit the 5000 hr mark on my L4310HST but I use synthetic universal hydraulic oil to increase my chances of having a long and trouble free life on the HST.

Rich

 

[JDgreen227]

I will never see the 5000 hour mark on my JD either...so I'm not too concerned about getting it to 10,000 hours.

Question.....does anyone know of a study where comparisons were made between conventional and synthetic hydraulic oil in identical tractors using the hydrostatic transmissions? If this is off topic, my apologies.

 

[kensfarm]

I'm almost at 1100 hours w/ my TC35D.. one thing I've noticed.. my engine temp. stays at normal operating temp pulling a two bottom plow.. but using the 72 tiller my temp rises above the normal operating temp.. both are from operating the tractor for 3 or 4 hour duration.