Editing Tractor (section)

== Operation ==
Modern tractors have many electrical switches and levers in the cab for controlling the multitude of different functions available on the tractor.

=== Pedals ===
Some modern farm tractors retain a traditional [[manual transmission]]; increasingly they have hydraulically driven powershift [[automatic transmission|transmission]]s and CVT, which vastly simplify operation.

Those with powershift transmissions have identical pedal arrangements on the floor for the operator to actuate, replacing a [[clutch]] pedal on the far left with an inching pedal that cuts off hydraulic flow to the clutches. Twinned [[brake]] pedals – one each for left and right side wheels – are placed together on the right side.  Some have a pedal for a foot [[throttle]] on the far right. Unlike automobiles, throttle speed can also be controlled by a hand-operated lever ("hand throttle"), which may be set to a fixed position.  This helps provide a constant speed in field work.  It also helps provide continuous power for stationary tractors that are operating an implement by [[power take-off|PTO]] shaft or axle driven belt.  The foot throttle gives the operator more automobile-like control over the speed of a mobile tractor in any operation.

Some modern tractors also have (or offer as optional equipment) a button on the gear stick for controlling the clutch, in addition to the standard pedal, allowing for gear changes and the tractor to be brought to a stop without using the foot pedal to engage the clutch.  Others have a button for temporarily increasing throttle speed to improve hydraulic flow to implements, such as a front end loader bucket.

Independent left and right brake pedals are provided to allow improved steering (by engaging the side one wishes to turn to, slowing or stopping its wheel) and improved traction in soft and slippery conditions (by transferring rotation to the wheel with better grip).  Some users prefer to lock both pedals together, or utilize a partial lock that allows the left pedal to be depressed independently but engages both when the right is applied.  This may be in the form of a swinging or sliding bolt that may be readily engaged or disengaged in the field without tools.

Foot pedal throttle control is mostly a returning feature of newer tractors. In the [[United Kingdom|UK]], foot pedal use to control engine speed while travelling on the road is mandatory. Some tractors, especially those designed for row-crop work, have a 'de-accelerator' pedal, which operates in the reverse fashion of an automobile throttle,  slowing the engine when applied. This allows control over the speed of a tractor with its throttle set high for work, as when repeatedly slowing to make U-turns at the end of crop rows in fields.

A front-facing foot button is traditionally included just ahead of the driver's seat (designed to be pressed by the operator's heel) to engage the rear [[locking differential|differential lock]] (diff-lock), which prevents wheel slip. The differential normally allows driving wheels to operate at their own speeds, as required, for example, by the different radius each takes in a turn.  This allows the outside wheel to travel faster than the inside wheel, thereby traveling further during a turn. In low-traction conditions on a soft surface, the same mechanism can allow one wheel to slip, wasting its torque and further reducing traction. The differential lock overrides this, forcing both wheels to turn at the same speed, reducing wheel slip and improving traction. Care must be taken to unlock the differential before turning, usually by hitting the pedal a second time, since the tractor with good traction cannot perform a turn with the diff-lock engaged. In many modern tractors, this pedal is replaced with an electrical switch.

=== Levers and switches ===
Many functions once controlled with levers have been replaced with some model of electrical switch with the rise of indirect computer controlling of functions in modern tractors.

Until the late of the 1950s, tractors had a single register of gears, hence one gear stick, often with three to five forward gears and one reverse. Then, group gears were introduced, and another gear stick was added. Later, control of the forward-reverse direction was moved to a special stick attached at the side of the steering wheel, which allowed forward or reverse travel in any gear. Now, with [[Continuously variable transmission|CVT]]s or other gear types, fewer sticks control the transmission, and some are replaced with electrical switches or are totally computer-controlled.

The three-point hitch was controlled with a lever for adjusting the position, or as with the earliest ones, just the function for raising or lowering the hitch. With modern electrical systems, it is often replaced with a potentiometer for the lower bound position and another one for the upper bound, and a switch allowing automatic adjustment of the hitch between these settings.

The external hydraulics also originally had levers, but now are often replaced with some form of electrical switch; the same is true for the [[power take-off]] shaft.