Lengevity and reliability of various transmission types

[dfkrug]

I find it hard to beleive that a JD 770 does not have some type of internal overrun clutch for the PTO to prevent that from happening.
Even my older 1978 JD 850 with single stage clutch and non-live PTO has an overrun clutch so a brush mower doesn't drive through the PTO pushing the tractor.

My B21 and my JD4300 were both HST units with no overrun clutches in the
the PTO drive train. The former had a simple one-stage dry foot clutch
that disconnected the engine from the drivetrain, mostly for PTO control.
The second eliminated the foot clutch entirely so another method had to
be used to engage the PTO. This is a trend in CUTs that we will see more
and more, and the makers are experimenting with a number of different
approaches. On the 4300, the PTO control is a fragile hand lever-controlled
wet clutch that is either all on or all off, and a wet clutch brake is used on
the same shaft. How many CUTs use PTO brakes? All the momentum of
a rotary mower being braked tended to break the brakes.

Another trend is the use of quieter helically cut gears in the range shift,
gearboxes, versus straight-cut gears.

Back to the OP's MF35.....the one I drove with the torque converter ran
its implement pump off the gearbox, not directly off the engine. This meant
that you have to rev up the engine a bit just to get the hyd pump to work.

 

[RobertN]

I just sold my Kubota(want a larger one). It was an 1985 manufacture. I sold it with 1200 hours, 800 of which were mine. Flawless. Mine saw mostly mowing work, with some drive maintenance, and some loader work.

Don't Bocat's and other skidsteers use a version of a HST drive? Those things get beat on hard, and work work work.

I am not sure I would consider HST a newer technology. It was not new when my Kubota was made in '85. The technolgy, and it's application are older than that.

As another poster mentioned, you hardly ever ever hear of broken HST's on this forum. I have been here 11, almost 12 years. It is few and far between that you hear of any tranny issues, gear or hydro.

 

[killdozerd11]

I have operated and worked on a lot of equipment and have learned that if you properly
maintain a piece of equipment the better off you will be..so change the oil and filters in HST and you won't have many problems.

Except bad operating will still brake anything reguardless

Words i will never miss was my old man saying
Got to put in another clutch in the XXXXING-loader,tractor,dozer
because the ******* he rented it to tore it out again

 

[JoelD]

Definately they more complex the more stuff to go wrong

I've had to have a hydraulic reverser rebuilt and that was not fun and was a lot more money than replacing clutch discs which by the way where the few parts I did not have to replace

I don't see, with all the seals in a hst how it could possibly last longer than geAr?

My ranger which is manual has 144k on it and the tranny is as strong as the day it was built

I don't know to many cars with auto's that can go that long knbetween rebuilds, none of mine have

Joel

 

[Matt_Jr]

My ranger which is manual has 144k on it and the tranny is as strong as the day it was built

I don't know to many cars with auto's that can go that long knbetween rebuilds, none of mine have

I've got a prius(cvt) with 178k, been through 2 suburbans(140k+each). My parents had 2 pontiac bonnevilles, one with 190k, the other with 250k. All sold with original transmissions. All autos. My Currant truck(04 silverado) pulls my tractor around and trailers full of fire wood, and has about 72k on it. The key is flushing the transmissions regularly. None of them were rebuilt. Automatic trannys today are built pretty good. As long as the fluid is changed regularly(every 20k) chances are pretty good they'll last as long as the engine.

 

[buck12]

Definately they more complex the more stuff to go wrong

I've had to have a hydraulic reverser rebuilt and that was not fun and was a lot more money than replacing clutch discs which by the way where the few parts I did not have to replace

I don't see, with all the seals in a hst how it could possibly last longer than geAr?

My ranger which is manual has 144k on it and the tranny is as strong as the day it was built

I don't know to many cars with auto's that can go that long knbetween rebuilds, none of mine have

Joel

I have a 93 F150 auto with 150,000 miles and the only thing ever done to the transmission was the addition of 1 qt of fluid at about 100,000 miles. Went to have the transmission serviced at about 75,000 miles and the mechanic advised me not service the transmission with that many miles. He said that his experience was that if you go well past service intervals and serviced auto transmissions that they often came back shortly needing a rebuild. Knock on wood I took his advice and she is still going strong.

 

[DGS]

I understand how they work certainly. I'm asking more about technical aspects of the units, not preferences in operations from owners.

I'm concerned about the reliability of the various units. HST is the cats meow for controllability of the machine. However I dont know how solid they are if you do a lot of ground engaging work. I dont know if anyone knows for sure, as I'm not sure if the larger machines (200+ HP) are even made with Hydro transmissions.

Without question a standard gear transmission can run all day with a heavy disc breaking new ground and wont even blink. But can hydro's do the same? I dont know.... But it is something I would take into account in buying a machine.

I buy and hold. I mean until the thing falls to pieces, and then I'll pay to get it duct taped back together.

So if a manual unit will last "forever" and a hydrostat needs rebuilt every 6 years if its worked hard the decision is easy as to which to buy....But maybe the hydrostat is just as solid..... I dont know.

All you have to do is look at all the huge ground engaging 4wd artculating tractors out there and that will answer your question about hydros.

 

[Soundguy]

All you have to do is look at all the huge ground engaging 4wd artculating tractors out there and that will answer your question about hydros.

And yet again.. big difference in a hst tranny.. and the things the average loader or bulldozer has in it............

soundguy

 

[Specop_007]

I wish I could edit the title. I cant believe I spelled longevity wrong.

 

[crashz]

that's not a trans problem.. that's a maintenance issue.

if the brakes in my truck need replacing I shouldn't complain that they don't last forever.. they are a WEAR item designed to be replaced. when they need it.. do it.

also.. IMHO.. clutch life is directly related to operator experience, with also a good portion based on type of work done.. I expect loader tractors with clutches to have them wear out faster.. etc..

soundguy

I agree. I should have clarified that I meant that the clutch system is not a simple as say an old 4 speed truck transmission. For me, the maintenance of a fluid system is easier that splitting a tractor and replacing the clutch.

The over-running is good point. I'll bring that up in another thread, so I don't hi-jack this one.