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silverta16

Why Did IH Make Hydro and Gear Drive?

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I'm new to the larger tractors, so bear with me. I understand exactly what the gear drive tractors are and how they work, like the 1066 for example. It's my understanding they made a hydro version of nearly all the 66 series as well? Exactly how do these tractors work? Do they have a lever like a hydrostatic lawn mower? Silly question but does the clutch still stop the tractor, and the lever just determines the speed? How about reverse, did it have a seperate lever or did you pull the hydro back? Could anyone post some pics of the controls on a hydro model? Thanks in advance.

I've also heard and read that the hydro tractors are great bailing tractors, why?

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When the series first came out there was the 966 Hydro and the 1066 Hydro. They only lasted a couple years until they were replaced by the Hydro 100.

Never had a hydro on a baler but did run a Hydro 86 a few times mowing ditches and it was a nice little setup. I think a 1066 Hydro with a 234 picker on it would be a corn eatin' machine ;) .

1974IHHayingAd.jpg

1975Hydro70Hydro100Ad.jpg

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I'm new to the larger tractors, so bear with me. I understand exactly what the gear drive tractors are and how they work, like the 1066 for example. It's my understanding they made a hydro version of nearly all the 66 series as well? Exactly how do these tractors work? Do they have a lever like a hydrostatic lawn mower? Silly question but does the clutch still stop the tractor, and the lever just determines the speed? How about reverse, did it have a seperate lever or did you pull the hydro back? Could anyone post some pics of the controls on a hydro model? Thanks in advance.

I've also heard and read that the hydro tractors are great bailing tractors, why?

As shown in the above picture there is one lever to control speed from forward to reverse. There is also a low and high range lever on the right side of the tractor where the shifters are on a gear drive. The "clutch" is called a foot and inch petal on the IH hydros. It can be used to stop the tractor but you can also pull the hydro lever to the N position to stop.

I suppose people say a hydro is a good baler tractor because you have infinte speed control without shifting as the size of the windrows vary.

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Single lever to the left of the steering wheel in the pic's IH986 posted controls speed & direction, push it forward to go forward, push it farther to go faster, pull it back for reverse. The lever sticking up on the right side of the wheel was a range lever, low was good up to 8 mph, High was good up to 20-21 mph depending on tire size.

Hydro's were excellent for PTO work, Been almost 40 yrs since the first 656 Hydro's were built and NOBODY has come up with anything better for PTO work like running balers, mowers, the larger tractors with cabs are especially good running PTO snow blowers. Run the engine @ PTO speed and control speed with the hydro. And they make great loader tractors too. Anything that required light drawbar pulling loads and high PTO power loads they worked great on, like planting, cultivating, spraying, chopping.

The "Clutch" was called the "Foot & Inch Pedal" which operated a dump valve for creeping like when hooking up to implements. IH's big tractor Hydro's used a variable displacement piston pump and variable displacement piston motor to stay efficient and offer a greater speed range. Most combines & lawn mowers use a gear pump and a variable speed motor. The entire pump & motor assembly was built in FARMALL's WHITE ROOM. It was THE place to work @ FARMALL, air conditioned, clean filtered air like in hospital operating rooms piped in..... You had to be somebody to get inside the white rom......I think I got in there ONCE in 5 years.

There is a horsepower limit to what the hydro's can withstand, that's why they never built anything bigger than 100-110 hp hydro's. That's normally big enough for what they were used for at the time. When used for heavy draft loads the power lose of the hydro's started to show up. The Hydro 100 for example lost 20% of it's maximum PTO HP at the drawbar while a 966 gear drive only lost about 15%.

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I have a Hydro 186 and love it for non tillage work. Everyone wants to drive the hydro!

However my neighbor bought a Hydro 656 new and hated it. Back then they plowed (turning plow) with every tractor they owned. He said the hydro whined so loud when pulling at full load it was unpleasant. They liked it for the mower conditioner and baling but found it unsuitable for tillage. They traded it in on a new (demonstrator) GOLD hooded 826 the dealer was having trouble moving. The only way they would buy the 826 was if the dealer would repaint it the proper red/white colors. I had the chance to buy the tractor about 15 yrs ago but didn't. At the time I didn't know the history of the gold hood or I would have. They only told me AFTER it was sold. Another neighbor has it (about 10 miles from here) and uses it lightly.

Thx-Ace

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Farmalltom.... Gittin it done with his 1026 and front mount blower...

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Farmalltom.... Gittin it done with his 1026 and front mount blower...

The arc of snow courtesy of an Erskine front-mounted blower? I always thought that hydro and the Erskine would be the ticket for blowing snow without a sore neck.

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Page 199 of IH Farm Equipment Product History gives a cutaway drawing and full explanation of how the IH hydro works.I can't duplicate the cutaway but I will quote the text."The swashplate controlled hydrostatic piston pump is directly connected to the tractor engine.When the operator moves the speed ratio control{the lever on the left},the hydraulic powered servo cylinder changes the angle of the pump swashplate.This changes the amount of high pressure oil flowing to the hydrostatic piston motor that is directly connected to the tractor final drive.The higher the volume of oil flowing to the motor,the faster it rotates,and faster tractor travel results.When the pump swash plate is in the neutral position,there is no pump output and the tractor stops.When the pump swash plate tilts past neutral,the oil flows in the opposite direction and the hydrostatic piston motor reverses and the tractor reverses.The hydrostatic pump and hydrostatic motor are mounted on the center section that also provides the interconnecting,high pressure oil passages."Also to quote,"The hydro tractors were ideal for baling,chopping and mowing where speed control with constant pto speed is a great advantage.It was handy for plowing and tillage and certain efficiences could be achieved,but that WAS NOT IT'S NUMBER ONE APPLICATION."Alot of the hydros got a bad rap simply because of lack of recommended maintenance and the farmer not really understanding the powertrain.Somewhere in one of my books I read that engineers who had developed hydro power for the guns on our big warships were employed by IH after the war and were chief designers on the IH Hydro drive.

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A lot of the hydros got a bad rap simply because of lack of recommended maintenance and the farmer not really understanding the powertrain.Somewhere in one of my books I read that engineers who had developed hydro power for the guns on our big warships were employed by IH after the war and were chief designers on the IH Hydro drive.

The ex military reference could very well be. The current US submarine fleet is run by a typical swash plate hydro system driving the big screws, and has been for a long time. Wobble plate systems came on when hydraulics got popular as precision parts became viable/available.

Ya think maintenance was a problem? :lol: I stayed away from anything agricultural for a long time simply because of things like the thread talking about air filters. If they don't understand changing filters then they got no business owning a hydro transmission.

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