The advancement of Hydro Transmissions

[machmeter62]

Since these transmissions have gained popularity, why haven't they been developed for eighteen wheelers ("Big Rigs")? Since most big cities freeways turn into "70 MPH parking lots" during rush hours, a drivers clutch foot might geat very painful!! Am I missing something here, as these drivers inch their way along these cities, constantly starting and stopping? Several years ago on this site, a gentleman from Canada had a fleet of Kubota tractors towing trailers along side highways for clean up maintenance purposes. He traded them because of high fluid temps in the hydro, poor performance, and high fuel consumption. I see Kubota has auxillary coolers for some of their hydros now?

 

[Texasgreen]

There are many reasons why most of your big rigs trucks you see on the highways don’t use hydro transmissions or better know as an automatic transmissions. Most big rigs don’t use them because an automatic transmission takes more hp to operate. The hydro transmission doesn’t like heat and also there is a slippage factor there due to a torque converter that will eat up your fuel efficiency due to slippage. Also, with an automatic transmission, you don’t have the down hill engine breaking control as you do with a manual transmission.

I had bought a Kubota 3130 HST 31HP, and my neighbor had a New Holland TC-29 manual shift 29HP. The NH tractor could work circles around my Kubota when it came to pulling anything heavy. The Kubota HST would get hot quick and start to get weak.

There are many pros and cons when it comes to choosing a tractor with a hydro drive transmission or a gear driven transmission tractor. Me. I like gears better.

Hope this helps.

 

[Dargo]

I've never had even the slightest desire to own a Montana tractor, so I cannot comment on their hydro transmissions since I've never even sat on a Montana tractor. However, the comments that hydro transmissions, particularly even mentioning Kubota, are not able to do any heavy work is simply a foolish statement. There are tens of thousands of hydro tractors working all over this country each and every day. With your distorted sense of reality, I suggest that you make sure that you never buy an car or truck with an automatic transmission. With your logic, they will never last. You'd be much better off driving a heater with a hog leg. Afterall, A/C also just draws hp away from the engine.

The debate between gear and hydro has been discussed at length here. Just spend a few days looking up old posts. Some people prefer gear tractors and some prefer hydro tractors. For someone to comment that hydro tractors simply heat up and cannot work only shows their lack of knowledge.

 

[MadReferee]

It's interesting to note that most heavy equipment bulldozers have had some form of hydrostatic transmission for many years now. If hydros were so bad or so inefficient then why are they still being used in this application? I believe all the big Cat dozers are hydro and have been for some time.

 

[machmeter62]

Texasgreen, Thanx for the reply. I live out in the mountain west part of the U.S. These newer 700 H.P. Peterbuilts/Kenworths, unless it is extremely steep terrain, hills don't faze them, and if you aren't going at least the speed limit, you are looking at a "radiator" or "hood ornament" in your rear view mirror! I think GM builds the best automatic transmissions in the world, which are also installed in Rolls Royce vehicles. I have three GM vehicles, all in trucks that have a "lockup torque converters" that engage at 43 MPH, and can be down shifted on hills for braking action. These are one 3/4 ton pickups however; maybe it's the internal clutches that would fail with more weight and extreme use? It could also be that moving parts syndrome; too many, subject to failure, which is another reason I've never enjoyed riding in a helicopter!!

 

[machmeter62]

Dargo, I truly enjoy reading all your comments and rerbuttals since you joined the site! We had to hire an attorney for an estate settlement recently, and his nickname was "PIT BULL."

 

[Egon]

"radiator" or "hood ornament" in your rear view mirror!

There are a lot of us that only see the bumper or the bottom of a moulded front end!

 

[Dargo]

Dargo, I truly enjoy reading all your comments and rerbuttals since you joined the site! We had to hire an attorney for an estate settlement recently, and his nickname was "PIT BULL."

Okay, I'll admit, sometimes I enjoy a good debate/argument.

 

[Texasgreen]

Dargo, did I step on your toes or something when I said what I said about my Kubota 3130 HST? “The Kubota HST would get hot quick and start to get weak.” I am not trying to knock the Kubota line of tractors in any way or fashion. I have a feeling that you might own a Kubota? I was just stating a fact about what my Kubota 3130 HST was doing in real world use. In fact, I had to have the directional change servo in the transmission changed out two times. After the second time the servo hung up on me, my lil orange tractor was just a memory for me and headache for the dealership that bought it back.

 

[TillerofdaEarth]

A Hydrostatic Transmission is not an "Automatic" tranny. It is entirely diffirent in it operation compared to an automatic trans.

Hydrostatic transmissions transmit all power with hydraulics; there is no solid coupling of the input and output. One half of the tranny is a variable displacement pump and the other half is a hydraulic motor. A movable swah plate controls the piston stroke to change the displacement.

An automatic trans basically uses hyd pressures to select the appropriate gear ratio without operator intervention and use a torque converter between the engine and transmission rather than a clutch.

I may be wrong, but to my knowledge I do not know of any manufacture that puts a Hydrostatic tranny in any of their large farm tractors. I just don't think they would hold up to the day in day out rigors of pulling heavy ground engaging equipment.

Hydros are great in compact tractors, lawn mowers, combines and the like. But Hey! I'm a gear guy.