Allison 1000/2000/3000/4000 Product Familiarization
Allison 1000/2000/3000/4000 Fleets Training
Allison 1000, 2000, 3000 and 4000 Transmissions are found
in a wide variety of vehicles around the world.
- These four Transmission offerings are grouped as Product Families –
the 1000/2000 Product Family and the 3000/4000 Product Family.
- Both Product Families share some key features and can be found in similar applications, the biggest difference being 3000/4000 Product Family Transmissions are typically found in larger vehicles and more heavy-duty applications than 1000/2000 Product Family Transmissions.
- The Transmission is located behind the Engine.
- The Engine crankshaft connects to and drives the Transmission input.
- The Transmission develops output rotation which is typically
supplied to the vehicle’s final drive or axle by a driveshaft or driveline.
Without a Transmission, the vehicle would be limited to a
single gear ratio making the vehicle very inflexible.
- Modern vehicles require the ability to accelerate from a stop,
handle a load, and attain normal road speeds.
- A single gear ratio typically provides either good low speed performance or good high speed performance – not both.
- A single gear ratio vehicle designed for low speed and load handling
performance will not perform well at road speed.
- A single gear ratio vehicle designed for road speed performance will
not handle loads or accelerate well from a stop.
Manual Transmissions typically rely on the operator physically
moving gears, using a manual shift selector, to manually select Transmission
ranges.
- In a basic Manual Transmission, gear ratios are based on the number
of teeth on two gears – the drive gear and the driven gear.
- When the operator manually shifts the Transmission, the
drive-to-driven gear tooth count changes and various ratios are created.
- A clutch is typically required to disconnect and engage Engine power
to the Transmission.
- Disengaging the clutch (foot pushing the clutch pedal), removes the Engine power from the Transmission.
- This allows the operator to make manual shifts and allows the Engine
to idle with the vehicle stopped and the transmission in range.
- Engaging the clutch (foot off the clutch pedal), mechanically
connects the Engine and Transmission input.
- The power from the Engine can be used by the Transmission to create
output when a moving range has been selected.
Allison Automatic Transmissions upshift and downshift
automatically and don’t require an operator-controlled clutch.
- The Allison Torque Converter connects the Engine to the Transmission
input.
- At a stop, Engine power is not transferred through the Torque Converter to the Transmission input.
- When Engine rpms increase, the Torque Converter drives the Transmission input.
- The Transmission Electronic Control and hydraulic systems work
together to automatically control shifts.
- Planetary gear sets consist of a Ring gear, Sun gear and a Carrier assembly which includes Pinion gears.
- Various output ratios are created
by holding and driving components.
- To decrease input speed (and
increase torque) the Ring gear is held, the Sun gear is driven, and the Carrier becomes the output mechanism.
- To increase input speed (and
decrease torque) the Ring gear is held, the Carrier is driven, and the Sun
gear becomes the output mechanism.
- A 1:1 ratio is achieved when no
components are held and two components are driven at the same speed.
- Reverse is created by holding the Carrier and driving either the Sun gear or Ring gear.
- The gear sets work together to
create the necessary output ranges, often using created output from one
gear set to drive components in other gear sets.
- Allison
Transmission clutch assemblies are multi-disc, consisting of an
alternating stack of fiber "friction" and steel "reaction" plates.
- Clutches are
applied by compressing the plates together using a piston forced by
hydraulic pressure.
- Clutches are
released by spring pressure when the hydraulic pressure against the piston
is exhausted.
- "Stationary" clutches hold planetary components or shafts.
- Rotating
clutches lock rotating components or shafts together.
- The Transmission Electronic
Control and hydraulic systems work together to apply and release clutches.
- The Electronic Control monitors
and adapts shifts to match driving conditions.
- The Electronic Control also
monitors inputs from vehicle systems to enable optional operational
features – for example, if programmed, the Electronic Control may prevent
shifts out of Neutral unless a signal is received indicating the operator
has depressed the brake pedal.
- A variety of optional features
are available depending on the Transmission configuration and intended use
(also referred to as the Vocational Model).
- For example, the HS (or "Highway
Series") Vocational Model is specific to vehicles which will only be
operated in "on road" conditions (not used off-road).
- The HS Vocational Model includes
1000, 2000, 3000 and 4000 Transmissions to satisfy a variety of Vehicle
and Engine sizes.
- Electronic programming features
and options are grouped into logical packages for the various on-highway
applications.
- And external feature availability
is matched to the vehicle’s intended use; for example, RDS Transmissions
are available with Power Take-Off (or "PTO") provisions because
applications utilizing these Transmissions typically require a PTO to
power various Vehicle features.
- The first number indicates
whether the Transmission is a 1000 or 2000.
- The second number identifies the Transmission gearing as either close or wide ratio, plus indicates whether
the Transmission includes a park pawl.
- A "5" in the third field
indicates a Transmission with a higher park pawl rating.
- The fourth field is reserved for
future designation use – it is currently "0" for all 1000/2000 Product
Family Transmissions.
- The Vocational Model identifier
appears at the end of the Transmission designation code.
#1000/2000 Product Family Bus Transmissions:
- The "B" indicates the Bus
vocation.
- "2" identifies the Transmission
as a 2000.
- "1" or "2" is used to identify
whether the Transmission includes a park pawl.
- 1000/2000 Transmissions used in
buses outside North America utilize designations described here, but can
be accompanied by a "T" prefix.
- Include the two-letter prefix "MD".
- The number "3" identifies the
transmission as a 3000.
- The second number field is either "0" or "5" to indicate close or wide ratio, respectively.
- The next field indicates the
number for forward ranges.
- The fourth numeric field is
reserved to indicate any major revisions.
- Suffixes can include P for PTO, R
for retarder, and RM to indicate the Transmission is an Allison
Remanufactured unit.
#Current 3000 Non-Bus designations:
- The first number in the
designation, "3" identifies the Transmission as a 3000.
- The second numeric field can
indicate wide or close ratio, or can indicate that the Transmission is
capable of 7 forward ranges.
- The remaining two numeric fields
are reserved for differentiators related to ratings, features or major
revisions.
- The Vocational Model identifier
appears at the end of the Transmission designation code.
#3000 Bus Transmission designations:
- "B" in the first field indicates
the Transmission is a Bus Vocational Model; and a "T" in that same field
indicates a Bus model that will be used outside of North America only.
- "300" or "400" identifies the Transmission as a 3000; "200" or "300" used with the "T" designator
indicates the Transmission is a 3000 used outside North America.
- Suffixes can include "P" for PTO, "R" for retarder, and "RM" to indicate the Transmission is an Allison
Remanufactured unit.
#B 3400 xFE:
- The B 3400 xFE is a Bus Transmission that departs from the standard designation code convention.
- The B 3400 xFE is based on the B
300/400 but with modifications for city and Transit Bus applications.
- Include the two-letter prefix "HD".
- The number "4" identifies the Transmission as a 4000.
- The second field is either "0" or "5" to indicate close or wide ratio.
- The next field indicates the
number of forward ranges.
- The fourth number is reserved as
an indicator for major revisions.
- Suffixes can include "P" for PTO, "R" for retarder, and "RM" to indicate the Transmission is an Allison
Remanufactured unit.
#Current 4000 Non-Bus designations:
- The first number, "4" identifies
the Transmission as a 4000.
- The second field can indicate
wide ratio, close ratio, or indicate that the Transmission is capable of 7
forward ranges.
- The remaining two numeric fields
are reserved for differentiators related to ratings, features or major
revisions.
- The Vocational Model identifier
appears at the end of the Transmission designation code.
#4000 Bus Transmission designations:
- "B" indicates the Transmission is
a Bus Vocational Model; "T" is used to designate Bus Vocational Models
outside North America.
- "500" indicates the Transmission
is a 4000; "400" when used with the T designator indicates the Transmission is a 4000 used outside North America.
- Suffixes can include "P" for PTO, "R" for retarder, and "RM" to indicate the Transmission is an Allison
Remanufactured unit.
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