Allison Transmission; Gear Ratios; Propeller Shaft; Brakes - PREVOST H3-45 VIP Owner's Manual

9-10 Technical Information
Full dress, dry weight: . . . . .2582 lb / 1174 kg

ALLISON TRANSMISSION

Allison World MH4000 electronically controlled six
speed automatic transmission (MH4000R with the
optional output retarder).

GEAR RATIOS

st
1
................................................ 3.51
nd
2
............................................... 1.91
rd
3
............................................... 1.43
th
4
................................................ 1.00
5 th
................................................ 0.74
6 th
................................................ 0.64
Reverse:
Converter:

PROPELLER SHAFT

Dana Spicer SPL250 type tubular shafts, provided
with heavy-duty universal joints.

BRAKES

The features of the braking system include a dual
system where the front and rear circuits are
completely independent from each other. The
brakes are air operated disc type brakes. The
emergency/parking brakes are located on the drive
axle. To ensure a constant running clearance
between pads and disc, the brakes are equipped
with a non- wearing,
mechanism.

BRAKE CHAMBER EFFECTIVE AREA

2
Front axle: . . . . . 24 in
Drive axle: . . . . . 24/24 in
2
Tag axle: . . . . . 16 in
4.80
1.90
automatic adjuster
2
(service /emergency)
PA-1619 Owner's Manual H3-45 VIP

AIR SYSTEM

Compressed air is provided by a twin cylinder,
31.8 cfm Wabco, gear-driven, water-cooled and
engine oil lubricated air compressor.

ANTILOCK BRAKING SYSTEM (ABS)

The antilock braking system has one Electronic
Control Unit (ECU) controlling a 6- sensor/5-
modulator (6s/5m) system. A wheel slip sensor is
mounted at each wheel.
The Electronic Control
maintenance free. Its operating voltage is 24 ± 6
volts DC. The thermal operating range for the
ECM is from -40 to 167°F (-40 to 75°C).
The solenoid control valves are maintenance free.
Their operating voltage is 24 (+4.8, -2.4) volts DC.
The rated current draw is 1.65 amps. The thermal
operating range of the solenoid control valves is
from -40 to 176°F (-40 to 80°C).

TROUBLESHOOTING AND TESTING

For detailed information, troubleshooting and
testing refer to Bendix booklet "Bendix Service
Data EC80 ESP Controller (SD-13-4986)" found
on the Technical Publications USB flash drive and
web site or use menu "Diagnostics" of the DID
(see "DRIVER INFORMATION DISPLAY (DID)
MENUS " on page 11
Features).
AUTOMATIC TRACTION CONTROL
(ATC) – ELECTRONIC STABILITY
CONTROL (ESC)
In addition to the ABS function, vehicle is
equipped with a Traction Control System (TCS)
feature. This feature is provided by the Bendix
ESP EC-80 controller. Bendix refers to this feature
as Automatic Traction Control (ATC). Bendix ATC
can improve vehicle traction during acceleration,
and lateral stability while accelerating through
curves. ATC utilizes Engine Torque Limiting (ETL)
where the ECU communicates with the engine's
controller and/or Differential Braking (DB) where
individual wheel brake applications are used to
improve vehicle traction.
The ESP EC-80 model controller also provides an
ABS- based Electronic Stability Control (ESC)
Module (ECM) is
in Section 5 Other