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One of the best answers to this FAQ was posted by EricG.NH so I copied for my own reference and since he hasn’t answered himself yet, I thought I’d let you know what he said as it is very informative. The "PS" is especially helpful! Congratulations on your new addition :o)
All 8Ns [and Jubilees] have two modes that the hydraulic lift can operate in. Automatic position control and automatic draft control. The little lever under the seat selects between these two modes. Vertical for position control, horizontal for draft control. It's usually refered to as the position control lever. The other, larger lever, is the touch control. The operation of the touch control lever depends on which mode the lift is in. In automatic position control mode, little lever vertical, the lift arms follow the touch control position. Move touch control 1/2 way up, and the lift arms move 1/2 way up. Once set the internals will attempt to maintain the position or height of the lift. So in the case of a slighty leaky lift, it will adjust itself to keep the same height. Automatic draft control, little lever horizontal, is a different beast altogether. In this mode the touch control lever sets the depth of an implement, like a plow. At first glance this seems to be the same thing, but it's not.
As an implement is dragged through the soil, the soil pushes back on the implement. This pushing force is translated back to the internals of the hydraulic system. Automatic draft control mode attempts to maintain this force. What this means is that if the front wheels drop the lift rises out of the soil. The lift senses this and drops the lift to compensate. And when the front wheels rise up, the lift digs in, resulting in a larger pushing force, and the internals raise the lift to compensate. This way the system maintains a constant depth even on hilly terrain, etc.
The constant depth is only maintained if the soil is uniform. Otherwise the system will raise and lower the lift when the soil becomes more or less dense. When not dragging an implement, the touch control lever acts like a three position switch in automatic draft control mode. They are intake, neutral and exhaust. Raise the touch control and the lift will begin to lift and will continue until the lever is moved lower to the neutral position or further to the exhaust position, where it will drop the lift. It's possible to set the height of an implement by placing the touch control lever in the neutral position at the right time, where it will neither intake or exhaust. But if the system is leaky, the lift will not compensate for leak down, like in automatic position control. In general, position control is used for non-drafting implements, scoops, mowers, hogs, etc.
Hope this helps,
Eric
P.S. Buy the manuals Good Luck with your tractor. John
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