Gear Box:
SITCO gearboxes are prepared from
the world best OEM manufacturers who maintain several different
standards in their production to match a world’s demands. Each
set of gear box is escorted with a relevant test report, quality
assurance, identification card, and technical data sheet.
Manual:
Manual transmission come in two basic types:
A simple but rugged sliding-mesh or unsynchronized /
non-synchronous system, where straight-cut spur gear sets are
spinning freely, and must be synchronized by the operator
matching engine revs to road speed, to avoid noisy and damaging
"gear clash", and the now common constant-mesh gearboxes which
can include non-synchronized, or synchronized / synchromesh
systems, where diagonal cut helical (and sometimes
double-helical) gear sets are constantly "meshed" together, and
a dog clutch is used for changing gears. On synchromesh boxes,
friction cones or "synchro-rings" are used in addition to the
dog clutch.
The former type is commonly found in many forms of racing cars,
older heavy-duty trucks, and some agricultural equipment.
Manual transmissions dominate the car market
outside of North America. They are cheaper, lighter, usually
give better performance, and fuel efficiency (although the
latest sophisticated automatic transmissions may yield results
slightly better than the ones yielded by manual transmissions).
It is customary for new drivers to learn, and be tested, on a
car with a manual gear change. In Malaysia, Denmark and Poland
all cars used for testing (and because of that, virtually all
those used for instruction as well) have a manual transmission.
In Japan, the Philippines, Germany, Israel, the Netherlands,
Belgium, New Zealand, Austria, the UK, Ireland, Sweden, France,
Switzerland, Australia, Finland and Lithuania, a test pass using
an automatic car does not entitle the driver to use a manual car
on the public road; a test with a manual car is required. Manual
transmissions are much more common than automatic transmissions
in Asia, Africa, South America and Europe.
Non-synchronous:
There are commercial applications engineered with
designs taking into account that the gear shifting will be done
by an experienced operator. They are a manual transmission, but
are known as non-synchronized transmissions. Dependent on
country of operation, many local, regional, and national laws
govern the operation of these types of vehicles (see Commercial
Driver's License). This class may include commercial, military,
agricultural, or engineering vehicles. Some of these may use
combinations of types for multi-purpose functions. An example
would be a PTO, or power-take-off gear. The non-synchronous
transmission type requires an understanding of gear range,
torque, engine power, and multi-functional clutch and shifter
functions.
Automatic:
Epicyclical gearing or planetary gearing are used in an
automatic transmission. Most modern North American, and many
larger, high specification German cars have an automatic
transmission that will select an appropriate gear ratio without
any operator intervention. They primarily use hydraulics to
select gears, depending on pressure exerted by fluid within the
transmission assembly. Rather than using a clutch to engage the
transmission, a fluid flywheel, or torque converter is placed in
between the engine and transmission. It is possible for the
driver to control the number of gears in use or select reverse,
though precise control of which gear is in use may or may not be
possible.
Automatic transmissions are easy to use. In the past,
automatic transmissions of this type have had a number of
problems; they were complex and expensive, sometimes had
reliability problems (which sometimes caused more expenses in
repair), have often been less fuel-efficient than their manual
counterparts (due to "slippage" in the torque converter), and
their shift time was slower than a manual making them
uncompetitive for racing. With the advancement of modern
automatic transmissions this has changed.
Since their inception, automatic transmissions
have been very popular in the United States, and some vehicles
are not available with manual gearboxes anymore. In Europe
automatic transmissions are gaining popularity as well.
Attempts to improve the fuel efficiency of
automatic transmissions include the use of torque converters
which lock up beyond a certain speed, or in the higher gear
ratios, eliminating power loss, and overdrive gears which
automatically actuate above certain speeds; in older
transmissions both technologies could sometimes become
intrusive, when conditions are such that they repeatedly cut in
and out as speed and such load factors as grade or wind vary
slightly. Current computerized transmissions possess very
complex programming to both maximize fuel efficiency and
eliminate any intrusiveness.
For certain applications, the slippage inherent
in automatic transmissions can be advantageous; for instance, in
drag racing, the automatic transmission allows the car to be
stopped with the engine at a high rpm (the "stall speed") to
allow for a very quick launch when the brakes are released; in
fact, a common modification is to increase the stall speed of
the transmission. This is even more advantageous for
turbocharged engines, where the turbocharger needs to be kept
spinning at high rpm by a large flow of exhaust in order to keep
the boost pressure up and eliminate the turbo lag that occurs
when the engine is idling and the throttle is suddenly opened.
Semi-automatic:
The creation of computer control also allowed for a
sort of cross-breed transmission where the car handles
manipulation of the clutch automatically, but the driver can
still select the gear manually if desired. This is sometimes
called a "clutch less manual," "dual-clutch," or "automated
manual" transmission. Many of these transmissions allow the
driver to give full control to the computer. They are generally
designed using manual transmission "internals", and when used in
passenger cars, have synchromesh operated helical constant mesh
gear sets.
Specific type of this transmission includes: Easytronic,
Geartronic, and Direct-Shift Gearbox.
    
     
 
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