PREVOST X3-45 VIP 2017 Owner'S Manual Download

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Other Features

5-22

TRANSMISSION RETARDER

The transmission retarder is an optional device
that helps to reduce the speed of a vehicle. It
improves vehicle control, increases driving
safety and permits more economical operation.
The retarder provides slowing power when it is
most needed, such as when descending
mountain roads, in stop-and-go traffic and on
crowded freeways.

The transmission retarder is a vehicle-slowing
device, not a vehicle-stopping device. It is not a
substitute for the service braking system. The
service brake must be used to bring the vehicle
to a complete stop.

The retarder is provided with control buttons on
the steering wheel and a lever on the steering
column (refer to “

CONTROLS AND INSTRUMENTS

”

chapter).

NOTE

Extended use will raise the temperature of the
transmission fluid.

The retarder helps to reduce speed on grades
without using the vehicle's conventional service
braking system. This virtually eliminates brake
overheating and reduces the risk of a runaway
vehicle. A retarder greatly increases the service
life of brake pads and discs, resulting in reduced
brake maintenance costs.

NOTE

The stoplights automatically illuminate when
the vehicle is slowing down after application of
the transmission retarder.

NOTE

For vehicles equipped with the Antilock
Braking System (ABS), as the wheels start to
lock-up on slippery roads, the output retarder
automatically deactivates until the wheels roll
freely.

ENGINE BRAKE

WARNING

A vehicle speed retarding device (such as
engine brake) is not intended to replace the
service brake systems on your vehicle nor
intended to bring your vehicle to a stop. A
vehicle speed retarding device is only
intended to reduce the speed of your vehicle

under certain conditions.

Several types of engine brake can be installed
or are standard on certain engines. All are
used to reduce wear on the vehicle brake
linings.

WARNING

When descending significant grades, use the
service brake as little as possible. If the
engine does not slow the vehicle to a safe
speed, apply service brake and shift to a lower
range. Let the engine (and engine brake) slow
the vehicle. Keep brakes cool and ready for
emergency stopping.

VOLVO ENGINE BRAKE (VEB)

On vehicles equipped with the Volvo Engine
Brake (VEB), the engine brake mode is by
default, set to the AUTO

mode at vehicle

start-up.

When running in AUTO

mode, the engine

brake is gradually applied to 100% of the braking
power when the driver

pushes the brake pedal

Since AUTO

mode will not reduce vehicle

momentum unless the brakes are applied, it will
have no impact on fuel consumption.

The driver can also choose two other modes
using the steering wheel switches; Engine brake
LOW

and engine brake HIGH

When set to the engine brake LOW

mode,

50% of the engine brake power will be applied
when the driver

releases the accelerator pedal

Using engine brake HIGH

will apply 100% of

the braking power.

It must be noted that since engine brake LOW

and engine brake HIGH

will reduce

vehicle speed upon release of the throttle pedal,
they may negatively impact fuel consumption if
used for extended periods of time.

On vehicles equipped with an engine brake
switch, it is possible to deactivate the engine
brake (OFF mode). To do so, the driver must
press the engine brake switch located on the left
side of the dashboard.

Engine Brake Switch