Fleet Maintenance - 16

The next evolutions in
Class 8 transmissions
A look at transmission
needs for all-electric
trucks, and spec'ing
trends of fully automatic
transmissions in
heavy duty trucks.
By Gregg Wartgow
According to Branden Harbin,
managing director of global marketing for Allison
Transmission, many linehaul
fleets have decided an AMT is
"good enough" at helping them
meet their objective, which is
to migrate away from a manual
transmission that is easier on
both drivers and technicians.
As linehaul fleets wait to see
where the trend toward full electrification goes, they are hesitant
to make the broader leap to fully
automatic transmissions. Allison
is a manufacturer of automatic
transmissions for medium and
heavy duty commercial vehicles.
Dave Genise, director of engineering for Eaton Vehicle
Group North America, agrees
with that assertion.

their intended functions in the
same way as the diesel counterparts," Genise says. "This means
being fully able to start on grades
and maintain highway speed on
hills when they are fully loaded.
The design strategy used by early
adopters in the commercial vehicle space for these large, heavy
vehicles has been to use direct
drive. While a simple approach,
these motors are excessively
large and heavy, and still cannot
perform to the same level as
the diesel trucks and buses.
"Eaton solves this challenge by
expanding the range of the electric
motor by adding an AMT specifically designed for electric vehicle
use," Genise continues. "The lower
gears are used to multiply the
motor torque without adding a
larger motor, and in most cases,
actually using a smaller, less costly
motor. Torque multiplication in low
gears allows the vehicle to start
fully loaded on grades without
compromise. The higher gears are
used to place the electric motor
in its most efficient operating
speed while at highway speeds,
thereby extending vehicle range."

An AMT intended for use in an
electric commercial vehicle has a
few differences from a diesel AMT.
The EV transmission will have fewer
gears overall since the instant
torque response available in the
electric motor allows for larger step
sizes and less overall ratio spread.
"There is also no clutch in the
system," Genise points out. "The
electric motor is controllable
from zero rpm and is directly
connected to the AMT input. Shift
synchronization is accomplished
through precise motor speed
control with no need to open
and close a clutch. The result is
extremely fast shift times with
nearly imperceptible torque gap."


As the linehaul segment generally
settles on an AMT, Allison's Harbin
says a fully automatic transmission
can provide additional benefits that
may resonate with certain fleets.
Class 8 vocational trucks such as
dump trucks and concrete mixers
have already moved toward fully
automatic transmissions. "These
types of trucks were dominated by
manual transmissions for years,
but this is where we've seen a lot of
our gains over the past five years,"
Harbin says. "This segment has
bypassed right over the AMT and
gone straight to a fully automatic."

"Electric buses and
trucks must perform

There are three reasons why.
The biggest one is reduced maintenance. "With an Allison transmission, you leverage the torque
converter every time you go to
launch as opposed to a starting
clutch," Harbin explains. "A torque
converter is not a wear item that
needs to be replaced. By compar-

		┬╗ Eaton is offering a full range of EV
AMTs for use in buses and trucks from
Class 4 to Class 8. A four-speed EV AMT
for Class 8 vehicles (pictured) is currently
in testing. An AMT for buses and medium
duty trucks is already on the market.
Photo courtesy of Eaton

16 Fleet Maintenance | May 2020

		┬╗Allison's 3414 Regional Haul
Series is a fully automatic
transmission geared toward
the regional haul segment.
The 3414 improves upon
Allison's 3000 Series model by
increasing acceleration by 25
percent and boosting power
to 410hp and 1,450 ft-lb of
torque. The 3414 is already being
incorporated into Freightliner's
Cascadia and M2 112 trucks.
Photo courtesy of Allison Transmission

ison, an AMT leverages a starting
clutch to get the truck moving."
As Harbin reminds, clutch
replacements can be costly. That
is why some vocational trucks
have opted to bypass an AMT.
"With something like a concrete
mixer that is highly utilized, a
fleet could see a couple clutch
replacements over the life of
the truck," Harbin says. "Each
replacement takes the truck out
of service for two or three days.
The fleet can't afford that."
Beyond Class 8 vocational trucks,
Harbin says there are other Class 8
segments starting to show interest
in fully automatic transmissions.
"When you look at the regional
haul segment, particularly pickup
and distribution fleets like PepsiCo
and Frito-Lay, our market share
skyrockets," Harbin relates. "These
fleets see the value proposition
of a fully automatic transmission.
These fleets must run at a higher
start/stop duty cycle, like in cities
where they need better maneuverability and faster launches to
clear intersections. At night, these
fleets might operate like more of
a linehaul route. Here they don't
necessarily need that torque
converter, but still appreciate the
fact that they don't have to worry
about clutch replacements."
For fleets of all types, reduced
maintenance is an important benefit.
Then it's about matching the right
performance, cost, and ROI for
the specific application at hand.


Fleet Maintenance

Table of Contents for the Digital Edition of Fleet Maintenance

Uptime: Expecting the unexpected
Editor's Note: Catching up on fleet maintenance
Maintenance considerations for manual versus automated manual transmissions
DPFs: Clean or replace?
Why Identify and track vehicle warranties?
Lube it or lose it
OTA: Supporting uptime remotely
Management: How fleets can benefit from having a SAMP
Training: Supporting today's students and tomorrow's techs
Diagnostics: Assessing aftermarket diagnostic solutions
Fleet Part & Components
Tools & Equipment
Guest Editorial: Keeping tire pressure at optimum levels
Fleet Maintenance - 1
Fleet Maintenance - 2
Fleet Maintenance - 3
Fleet Maintenance - 4
Fleet Maintenance - 5
Fleet Maintenance - 6
Fleet Maintenance - 7
Fleet Maintenance - Uptime: Expecting the unexpected
Fleet Maintenance - 9
Fleet Maintenance - Editor's Note: Catching up on fleet maintenance
Fleet Maintenance - 11
Fleet Maintenance - Maintenance considerations for manual versus automated manual transmissions
Fleet Maintenance - 13
Fleet Maintenance - 14
Fleet Maintenance - 15
Fleet Maintenance - 16
Fleet Maintenance - 17
Fleet Maintenance - DPFs: Clean or replace?
Fleet Maintenance - 19
Fleet Maintenance - 20
Fleet Maintenance - 21
Fleet Maintenance - 22
Fleet Maintenance - 23
Fleet Maintenance - Why Identify and track vehicle warranties?
Fleet Maintenance - 25
Fleet Maintenance - 26
Fleet Maintenance - 27
Fleet Maintenance - 28
Fleet Maintenance - 29
Fleet Maintenance - Lube it or lose it
Fleet Maintenance - 31
Fleet Maintenance - 32
Fleet Maintenance - 33
Fleet Maintenance - OTA: Supporting uptime remotely
Fleet Maintenance - 35
Fleet Maintenance - Management: How fleets can benefit from having a SAMP
Fleet Maintenance - Training: Supporting today's students and tomorrow's techs
Fleet Maintenance - Diagnostics: Assessing aftermarket diagnostic solutions
Fleet Maintenance - 39
Fleet Maintenance - Fleet Part & Components
Fleet Maintenance - Tools & Equipment
Fleet Maintenance - Guest Editorial: Keeping tire pressure at optimum levels
Fleet Maintenance - 43
Fleet Maintenance - 44