Importance of Manual Mode in Automatic Transmissions
Modern automatic transmissions are justly
considered by many to be more comfortable and efficient gear shifting solutions,
and no wonder that major car makers give preference to advanced automatics over
conventional manual transmissions, thereby gradually making the latter a relic
of the past. The trend of shifting to automatics is especially vivid on the US
market, where the take rate of manual cars hardly reaches 2%.
Rapidly growing share of automatic
transmissions in modern vehicles made it possible to increase the level of
comfort on the road, optimize the process of gear shifting and fuel economy,
and to implement some features related to the road safety. All these benefits
are particularly important on urban roads with heavy traffic. But why designs
of automatic transmissions still include a manual mode of operation?
Transmission manufacturers include this feature
for a reason, as drivers frequently have to deal with some situations on the
road, when it is necessary to shift gears manually. In this article, we will
consider how this feature can be implemented in automatic transmissions, and
more importantly, when this mode of operation should be engaged.
Ways to implement a “manual mode” in automatic transmissions
Most of all automatic transmissions, in one way
or another (Tiptronic, Overdrive, kick-down etc), allow owners of automatic
vehicles to simulate the sequential manual control, as the actual gear shifting
is still fulfilled by the TCM, while the driver decides what gear should be
engaged.
Activating manual mode is not the same for all
brands. Switching to the manual mode and further control in automatic
transmissions with a Tiptronic function is implemented by moving the shift
lever into D and then move the lever to the Tiptronic shift gate marked with
symbols “+” for upshifting and “-“ for downshifting. In some cars, manual mode
can be actuated by means of paddle shifters.
Some automatic cars have an operating mode named “overdrive” (or O/D). This mode is engaged when the driver presses a special button located on the gear lever, thereby triggering forced engagement of the highest gear.
Manual/Sports Mode in BMW 3 Series
In the latest BMW 3 Series, manual mode is
bundled with Sport mode. Thus, when the driver moves the knob into this gate,
the car goes into Sport mode first. To start shifting gears manually, the
driver has to nudge the knob.
Commonly, the transmission remains in manual
mode until the driver slides the gearshift lever back into the D setting.
Performance-oriented models, such as Mercedes-AMGs, come with a special M
button. Pressing it puts the transmission in manual mode on a permanent basis.
Not all vehicles can remain in manual mode permanently: if the driver doesn’t
switch back to the original auto shifting, the system will do it automatically.
It is caused by the fact that in some
cars manual mode will enable the driver to repeatedly redline the engine. This
increases engine wear, especially if you do it when the motor is still cold.
Situations When It is Better to Switch Automatic Transmission to Manual Mode of Operation
Overtaking
During the overtaking maneuver, the driver has
to quickly change lanes to overtake the car moving ahead of him. To perform
this task properly in automatic cars, it is more convenient to use manual mode (Tiptronic)
for a hard acceleration, as the driver has to swerve into oncoming traffic for
a short time. When the driver switches to manual mode, he can select a more
suitable gear for rapid overtaking, as in manual cars. If there is no Tiptronic
mode in the car, it is possible to use the overdrive function to perform the
maneuver.
Icy Roads
It is also recommended to shift gears manually
in automatic cars when driving on icy roads. In some situations, roads covered
with snow, ice may affect the transmission operation, and it can engage the
wrong gear or perform automatic shifting at a wrong time. High speeds on the
ice-covered ground may also lead to road accidents. Thus, it is better for the
driver to be in charge of the gear shifting process to keep the car in lower
gears, not allowing the engine to increase the RPM rate. Some automatics even
have a special button with a snowflake icon, the use of which, leads to the
blocking of 1-st gear (it helps when moving uphill).
Upward sloping roads
When driving up the road for a long time,
especially when there are many cars ahead and the driver has to perform
overtaking maneuvers, the engine requires more power and torque. The necessary
operating parameters can be obtained at lower gears; otherwise the engine will
be exposed to excessive loads and the gearbox will shift too often. Therefore,
switching to manual mode will prevent premature wear of the main powertrain
components. However, it should be noted that modern automatics are quite
“smart”, as they “understand” when the car moves on upward sloping roads and
adjust to the situation. When it comes to cars equipped with older automatics,
drivers should take control over the process of gear shifting.
Off-roading
Unlike cars equipped with manual transmissions,
automatic cars are ill-suited for off-roading. Even modern automatic
transmissions may have a hard time, if the car gets on mud-locked roads. Under
such severe conditions, automatic transmissions frequently overheat or even get
out of order. But there is no need to panic, if your automatic car happens to
run on a bad road section. It is recommended to switch to manual mode of the
transmission operation, then reduce speed to 20-30 km/h and engage 2-nd gear.
In cases when the car gets stuck in the mud or moves very slowly, it is
recommended to engage “L” and “2” gears alternately. And by doing so, you’ll
avoid excessive acceleration and get the right amount of torque to travel on a
heavy stretch of the road without significant difficulties.
Engine braking
Each car owner should remember about such a
thing as engine braking. It is used in emergency situations, when the use of
standard brakes is impossible. The principle of engine braking in automatic
cars does not differ much from cars equipped with manual gearboxes. It is
necessary to lower gears from that currently engaged gear to “L”. The same algorithm
is applied in Tiptronic transmissions. Firstly, it is necessary to maximally
reduce the speed, and then switch the lever to the “L” position.
Learn more about the use of engine braking in cars with automatic transmissions
All in all, manual mode in automatic cars can be extremely helpful in challenging situations on the road, as it helps to simplify handling a vehicle and to reduce loads on its key components.
