Automated or Automatic — What’s the Difference, and Which One is Right for Me?
With new transmission options featuring advanced technologies now available, fleet managers are faced with an impactful decision to make when building a truck that will perform optimally in its designated application.
And in the case of transmissions, the rewards for making the right choice are clearly tangible where it matters most, in terms of fuel economy, weight savings and driver satisfaction.
Yet customers say there remains some confusion in the market about the differences between automated and automatic transmissions, how they compare to manual transmissions and how they may benefit customers in certain applications.
So First Class asked Peterbilt Assistant Chief Engineer Darryl Oster to explain the difference.
“First of all, it’s important to note that we’re seeing an industry-wide trend from manual transmissions to automated or automatic transmissions,” said Oster, who noted that about 60 percent of Peterbilt Class 8 trucks sold in 2017 were spec’ed with either an automated or automatic transmission. “Fleet-wide, they offer greater fuel economy, reduced driver fatigue, easier driver training and improved operation versus trucks spec’ed with manual transmissions. And fleets are getting better driver performance with automatic and automated transmissions.”
Oster noted that in some applications, an experienced driver with a manual transmission may outperform fleet averages, but experienced drivers trained on a manual transmission are a dwindling resource.
“With automated and automatic transmissions, fleets have greater assurances that their trucks will perform properly,” said Oster. “Just about any driver who gets in that truck will operate it the way it’s designed to be run.”
Torque converters vs. clutch
The key difference between the automated and automatic transmissions, according to Oster, lies in the use of a torque converter. “In an automatic transmission the torque converter takes the output from the engine and transfers that torque, which allows the transmission to shift gears,” said Oster.
Peterbilt offers several of the latest automatic transmissions available from long-time supplier Allison.
“In an automated transmission like the new PACCAR 12-speed Automated Transmission, there is no torque converter because the automated uses a clutch,” said Oster. “The shifting and gear change activity is similar to disengaging the clutch on a manual transmission. The pneumatic activation of the transmission occurs and enables the shift and this event happens quickly inside the PACCAR Automated Transmission, resulting in a very smooth gear change.
“The PACCAR Automated Transmission was designed and developed to complement the highly efficient PACCAR Powertrain which includes the PACCAR MX Engine(s) and a PACCAR 40K Tandem Rear Axle, providing the driver with a premium driving experience.
“A powerful feature available in the PACCAR Automated Transmission is ‘Urge to Move,’ which enables the truck to move forward upon releasing the service brake. This is similar to an automatic transmission where if you’re in drive, you’re in gear, so you move forward once you take your foot off the brake.
“All in all, the Powertrain represents the latest advancement in transmission technology and brings a level of functionality, ease of drive and driver friendliness for a fraction of the cost of an automatic.”
Real benefits
The first release of the PACCAR Automated Transmission is designed and optimized specifically for line-haul customers. The overall benefits of the PACCAR Automated Transmission are tangible, Oster reported. “For example, having no torque converter with the PACCAR Automated Transmission means lower chassis weight and greater payload — up to 417 lbs. lighter when compared to a TC-10 automatic transmission.”
Additionally, Oster noted that “an integrated PACCAR Powertrain, featuring an MX Engine, a PACCAR Automated Transmission and a PACCAR Tandem Axle, provides a 5 percent fuel economy improvement over prior years’ drivetrains.
“Peterbilt continues to help customers maximize their performance, not only with the PACCAR Automated Transmission but the fully integrated PACCAR Powertrain,” said Oster. “However we remain committed to offering our customers a choice of options to spec a truck best suited for their unique application, and that means providing transmission options that ensure Peterbilt trucks deliver a premium driving experience and the performance our customers demand, day in and day out.”