For heavy-duty fleet vehicles, there are currently three different transmissions commonly available—automatic, automated manual, and manual. In recent times, the trend in the industry has been to move to automatic transmissions. In North America, automation rates are estimated to have increased from approximately 70% to 95% in the past 10 years. But why is this?
According to Allison Transmission, a leading manufacturer of fully automatic transmissions for medium- and heavy-duty commercial vehicles, this uptake may be due to the reduced costs and easier maintenance associated with automatic transmissions. When combined with improved vehicle uptime, this results in a lower lifetime cost, which is a strong economic argument for automatic transmissions.
But what else is driving this trend, and what does this mean for the transmission fluid that operators should be using?
The benefits of automation
The continued journey for improved fuel economy and the evolution of alternative fuels have both been key drivers behind medium- and heavy-duty fleets transitioning to automatic transmissions.
See also: AMT service shifts forward
Automated manual transmissions (AMTs) are well known for improving fuel economy. In fact, research from the North American Council for Freight Efficiency has also found that fleets are realizing a 1% to 3% improvement in fuel economy by using AMTs over manual gearboxes. Comparatively, a 2015 study by Frost & Sullivan found that automatic transmissions can improve fuel economy by 3% to 5%.
Fleets are increasingly being encouraged to take a holistic approach to improving fuel economy. In the past, owners and operators mainly focused on the engine oil, but there are several driveline components, including the transmission and the gearbox, to consider. It’s therefore no surprise that automatic and automated manual transmissions are becoming more prevalent as operators take advantage of the efficiencies that can contribute to a reduced total cost of ownership.
Alongside fuel economy benefits, AMTs have the added benefit of reducing maintenance costs. AMTs require fewer clutch repairs compared to manual transmissions, which can suffer from improper shifting and overuse of the clutch brake. Both AMTs and automatic transmissions also enable drivers to have greater focus on the road rather than gear shifting, which can help reduce driver fatigue.
Initially, manual transmissions are less expensive and are considered a cost-effective option, especially for fleets with experienced drivers. However, automatic or automated manual transmissions significantly reduce the impact of driver behavior, so when total lifetime cost of training, maintenance, and fuel consumption are considered, automatic and automated manual transmissions can offer a more cost-effective solution.
What does this mean for the lubricant?
This general trend towards automation affects the type of transmission fluid that fleets require. Automatic, automated manual, and manual transmissions have specific hardware architecture that will require different friction modifiers, as well as different levels and types of anti-wear additives and corrosion protection additives for the hardware’s soft-yellow metals.