Which truck transmission should I buy?
It’s the age old trucking debate, as polarising as Holden versus Ford, AFL or NRL, and Batman or Superman.
Every driver has an opinion on transmissions and similarly every fleet operator or procurement officer will throw his or her two cents in when repairs, running costs and efficiency comes into the frame.
So which transmission should you specify for your new truck(s)?
To get the best out of your drivers and your equipment, there’s a couple of things to consider when selecting which truck transmission, be it a manual, automatic or an automated manual transmission (AMT).
It’s a factor driving every business in this day and age. We’re forever hunting for ways to curb spending and run operations as frugally as possible. And if you’re in the transport game, fuel costs are right at the top of the hit list.
As far as transmissions go, it’s difficult to say which gives you the better mileage edge, as driver behaviour and road experience plays a key role, especially in the operation of manual transmissions.
That said, a case study undertaken by the Green Truck Partnership, out of the Roads and Maritime Services and the Road Transport Authority (RTA) in NSW, revealed that Automated Manual Transmissions (AMT) delivered a fuel efficiency benefit in the order of 11 per cent compared with a fully automatic transmission – during field testing. That’s not bad going at all on the fuel economy front.
Not only do automatic transmissions (and AMTs for that matter) offer driver comfort and ease of use, they can also help you achieve greater productivity as well.
As any long-haul driver will attest, every time you make a shift in a manual transmission, you briefly take your foot off the throttle and lose some momentum. When you add up those seconds over a week of driving for example, the total time lost starts to add-up very quickly.
US-based Allison Transmission is the world’s largest manufacturer of commercial-duty automatic transmissions. They claim the powered shift of an automatic transmission gains anywhere from four to seven seconds every 400 metres travelled.
So again, when you consider the time saved over a year of operation, the productivity of an automatic transmission – especially operating within stop-start urban environments – can be strongly argued.
Picture this. You’re floating a 30 tonne excavator from a standing start. There are a number of variables that come to bear in safely shifting a load like that without spinning the tyres and losing traction – and a truck’s transmission plays a vital role.
Automatic transmission types, in most cases, allow for greater flexibility, manoeuvrability, traction and gradability (the steepest grade a truck can climb with a full load) on less than favourable terrain or gradients (incline or slope).
Automatic transmissions provide continuous power and torque to the wheels, meaning critical power to the drive-wheels isn’t interrupted at a time when it’s needed most.
Specifying an automatic or AMT with a torque converter will help your drivers (especially those with less experience) negotiate these sorts of loads more safely and effectively.
When operating a truck with a manual transmission, the risk of a roll-back on steeper gradients is ever-present, even if your driver is a seasoned professional.
One way to reduce roll-back though is to specify either a fully automatic transmission or an AMT with a torque converter.
Many contemporary automatics and AMTs include Hill Start Aid (HSA) technology as well as grade and weight sensing computation that instantly deliver torque through a converter and into the driveline.
Much like the traction scenario, this means power is never lost whilst a clutch is engaged, or whilst feet are frantically reaching for pedals.
Cost and lifecycle
The increased complexity of an automatic transmission drives your initial outlay and servicing costs up, while a manual set-up will nearly always be the least costly option both to specify and service/replace.
You should consider both the fuel economy and productivity sections of this blog when weighing up the initial cost of an auto or AMT though. If these transmissions suit your application, they’re likely to pay for themselves over a fairly short period of time.
The type of transport work being undertaken should be a key consideration in your decision-making around transmissions. This list put together by international freight giants Toll, covers most major road freight applications and can give you an idea of where your business fits in.
From small parcel delivery through to ‘out of gauge’ loads, the size and weight of road tasks vary considerably, so not only do your driveline specs need to be spot on, your choice of transmission must also match the task at hand.
The short answer is ‘horses for courses.’
It’s hard to go past a fully automatic transmission or an AMT for many vocational applications, particularly in stop-start, urban environments. Generally speaking, they’re simpler to use and they free up your driver to concentrate on the road/route.
But, there are still a lot of highly experienced drivers out there who can get the most out of a manual transmission. In the hands of the right driver, those gearboxes are essentially bulletproof. If you’re a fleet and you’re blessed with an abundance of experienced drivers, and upfront costs are still your primary expense driver, then it’s hard to argue with manual transmissions.
Whatever business you’re in, and before you make any lasting decisions, its worth considering at least some of the points above in reference to the skills-set and experience of your driving team.
To find out more about Isuzu’s Automated Manual Transmission, check out this instructional video specific to Isuzu’s freight king, the F Series range.