june2021 - 19

COMMERCIAL VEHICLE
CLUTCH CARE
Spec'ing, service, and repair considerations to
maximize the life of manual and AMT clutches.
By David Brierley
[ POWERTRAIN ]
B
efore the early 2000s, a heavy duty commercial
vehicle with anything other than a manual transmission
was almost unheard of. Since then, demand
for automated manual transmissions (AMTs) has
increased; gradually at first, then more quickly as
the technology became smoother and more reliable.
Fleets began to see the benefits of using AMTs:
They could be more efficient than a manual, plus new,
less experienced drivers could operate them, widening
the pool of viable candidates - a relief fleets are
happy to embrace considering the driver shortage.
Today, AMTs are spec'd on the majority of new
commercial vehicles rolling off the factory line.
Despite this trend, however, manual transmission
trucks are still desirable to many fleets.
" We still see demand for manual transmissions
from fleets with experienced driver pools and in
specific applications like heavy haul or severe
service, " said Becky Parsons, global clutch product
strategy manager at Eaton Vehicle Group.
To determine whether manual transmission or
AMT trucks are the best fit, fleets need to take a
variety of factors into consideration.
Transmission spec'ing basics
Manual transmissions may still make more sense
for some fleets. This can be the case for fleets with
a large pool of experienced drivers who prefer to
drive a truck equipped with a clutch pedal rather
than an AMT, or fleets whose vehicles are used in
more extreme duty cycles.
Applications the truck will be used in is one of the
most important considerations when spec'ing the
transmission. This can be especially critical since
some AMTs are limited in how much torque they
can handle.
" Customers need to look at what application the
trucks will go into, " said Chad Seth, director of truck
sales at Rihm Kenworth. " Specifically, a truck that
pulls an end-dump or side-dump may need a specific
type of AMT or go to a fully [automatic] Allison
transmission due to the low gearing needed. Some
AMTs only have limited torque capacities. "
Where an AMT may only be able to accommodate
a maximum torque rating of 1,850 ft-lbs, an
18-speed manual transmission could handle up to
2,050 ft-lbs, Seth said.
The majority of fleets without extreme torque
needs, however, can expect to see improvements
in almost every efficiency metric by making the
switch from manual transmissions to AMTs. This is
due mostly to the fact that drivers - experienced or
not - can more easily take advantage of the features
AMTs offer to improve efficiency.
" The biggest difference between AMTs and manuals
is that with AMTs, more features and functions
can be provided by the truck OEM in critical areas
of response, performance, and fuel efficiency, " noted
Johan Agebrand, product marketing director at
Volvo Trucks North America.
With proper training, fleets can expect more of
their drivers to utilize the AMT features and, therefore,
improve performance, he added.
" The top 5 to 10 percent of manual drivers might
not improve drastically with an AMT, but the other
90 to 95 percent certainly will, " Agebrand said.
" The biggest difference between
AMTs and manuals is that with
AMTs, more features and functions
can be provided by the truck OEM
in critical areas of response,
performance, and fuel efficiency. "
Johan Agebrand, product marketing director,
Volvo Trucks North America
June 2021 | FleetMaintenance.com
19
http://www.FleetMaintenance.com

june2021

Table of Contents for the Digital Edition of june2021

Uptime: The path to predictive maintenance
Editor's Note: Using resources wisely
Equipment: Getting to the bottom of air brake system leaks
In the Bay: Commercial vehicle clutch care
Shop Operations: How digitizing driver communication can improve maintenance
Fluid & Filtration: Why fleets shouldn't skimp on oil filters
Technology Trends: Gaining an advantage
Management: KPI fundamentals
Economic Outlook: Economic recovery update
Fleet Parts & Components
Tools & Equipment
Classifieds
Guest editorial: Benefits of remote brake system monitoring
june2021 - 1
june2021 - 2
june2021 - 3
june2021 - 4
june2021 - 5
june2021 - 6
june2021 - 7
june2021 - Uptime: The path to predictive maintenance
june2021 - 9
june2021 - Editor's Note: Using resources wisely
june2021 - 11
june2021 - Equipment: Getting to the bottom of air brake system leaks
june2021 - 13
june2021 - 14
june2021 - 15
june2021 - 16
june2021 - 17
june2021 - In the Bay: Commercial vehicle clutch care
june2021 - 19
june2021 - 20
june2021 - 21
june2021 - 22
june2021 - 23
june2021 - Shop Operations: How digitizing driver communication can improve maintenance
june2021 - 25
june2021 - 26
june2021 - 27
june2021 - 28
june2021 - 29
june2021 - 30
june2021 - 31
june2021 - 32
june2021 - 33
june2021 - Fluid & Filtration: Why fleets shouldn't skimp on oil filters
june2021 - 35
june2021 - 36
june2021 - 37
june2021 - Technology Trends: Gaining an advantage
june2021 - 39
june2021 - Management: KPI fundamentals
june2021 - Economic Outlook: Economic recovery update
june2021 - Fleet Parts & Components
june2021 - 43
june2021 - Tools & Equipment
june2021 - 45
june2021 - 46
june2021 - 47
june2021 - 48
june2021 - Classifieds
june2021 - Guest editorial: Benefits of remote brake system monitoring
june2021 - 51
june2021 - 52
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