Agriculture Reference
In-Depth Information
mission shift levers. Commonly, the range shift lever provides four major speed changes,
such as slowest, slow, medium, and high range. The gearshift lever provides four smal-
ler gear changes with each range. This results in sixteen forward and sixteen reverse gear
speeds.
Manual shift (standard) transmissions
are durable and ideal for pulling heavy loads, but
they are not handy. Manual transmissions are best shifted when the tractor is not in motion.
Shift while the tractor is moving and you'll get grinding, because the two gears that are
trying to mesh are rotating at different speeds.
A
synchro shift transmission
is a standard transmission with synchronizers that minimize
grinding when you shift between specified gears when the tractor is in motion. The clutch
pedal must be depressed when you shift, but the tractor motion does not have to be stopped.
A
shuttle shift transmission
synchronizes forward and reverse and allows you to shift
back-and-forth between the two with one movement. Shuttle shift is handy for repetitive
back-and-forth operations like picking up a bucket of manure, backing up, then moving
forward to load it into a spreader.
A
power shift transmission
allows you to shift between different speeds while the tractor
is in motion without using the clutch pedal, much like an automatic transmission in a truck.
Hydrostatic transmissions
are controlled by a foot pedal that allows you indefinite
speeds. When you take your foot off the pedal, the tractor stops, which is a good safety
feature. These types of transmissions are common in utility vehicles.
Hydraulics
Hydraulics is a system of pressurized hydraulic oil that transfers power via its hoses and
fittings to operate implements that have hydraulic pistons and cylinders. It also raises and
lowers the three-point hitch and powers the front-end loader.
Bar Hitch
Most tractors have a straight bar hitch: a frame-mounted bar of steel at the rear of the tractor
where implements can be attached. The straight bar hitch is used for pulling trailers, wag-
ons, and some discs and harrows.
Three-Point Hitch
A three-point hitch is the linkage on the back of the tractor that is hydraulically powered to
raise and lower equipment such as discs, plows, posthole diggers, and so on. The two side
arms, also called
lift arms
or
draft links,
serve to both lift and pull. The top arm, called the
