Allison Purpose-Builds More Powerful TerraTran Transmission
Engineers ruggedized the proven Allison 4000 Series on-highway transmission for a new variant suited to harsh off-highway operating conditions.
After more than two years of field testing and development, Allison has launched its new TerraTran off-highway transmission designed to meet the harsh operating conditions common in mining and hauling applications. Adapted from Allison’s 4000 Series on-highway transmission, this variant was developed based on extensive voice-of-customer input.
“We collaborated with several of our OEM partners in the development of the Allison TerraTran,” Kartik Ramanan, executive director of Global Off-Highway, Customer Support and Service Engineering, Allison Transmission, shared with SAE Media. “Voice-of-customer input indicated a need for the proven reliability and durability of the 4000 Series along with enhanced functionality including increased horsepower, torque and gross vehicle weight (GVW) capability, and the addition of fast reverse functionality.”
These enhancements were achieved through a combination of new gear ratios, power flow and improvements to internal components including gearing and bearings, Ramanan said. The TerraTran delivers maximum power of up to 800 hp (597 kW) depending on the application in which it is deployed, a significant increase from the 4000 Series transmission’s 605-hp (450-kW) rating. Maximum input torque ranges from 1,950 to 2,360 lb-ft (2,644 to 3,200 Nm), which is also a significant boost from the 4000 Series’ rating of 1,850 lb-ft (2,508 Nm).
The transmission also features seven forward and two reverse speeds. The fast reverse capability delivers improved productivity and optimized efficiency, Ramanan said. Field tests have demonstrated that TerraTran delivers enhanced drivability, gradeability and maneuverability under demanding operating conditions.
Seamless vehicle integration was a major focus of the new variant’s development process. “When developing this new propulsion system, one of our goals was to simplify installation of the TerraTran by maintaining 4000 Series packaging, which is not a simple task given that we were seeking to increase power output and ruggedness as well as add additional speeds including a fast reverse,” Ramanan told SAE Media. “However, our terrific team of engineers and innovators accomplished just that. We maintained the overall dimensions of the 4000 Series transmission package to enable customers to seamlessly integrate the new model into existing vehicles.”
The first customer application for the TerraTran, announced in July 2021, is Xuzhou Construction Machinery Group’s (XCMG) all-terrain crane. The release of TerraTran in the all-terrain crane is expected to further enhance the differentiated performance and value of XCMG products in the market, a spokesperson for XCMG Research and Development said in a statement. The collaboration takes the two companies’ decade-long cooperation “to the next level.”
Bell Equipment Group Services (BELL) will be the first customer to integrate the TerraTran into articulated dump trucks. BELL is evaluating the new transmission for its next-generation vehicles. “Our collaboration with XCMG and BELL are examples of Allison’s commitment to working closely with our OEM customers to develop innovative solutions designed to meet their unique needs and deliver unparalleled performance and productivity to end users,” Ramanan said.
Purpose-built for off-highway applications such as mobile crane, articulated dump truck and wide-body mining dump trucks, the new TerraTran transmission was designed with enough application flexibility to enable Allison to target multiple additional on-highway opportunities, Ramanan noted. TerraTran production commenced in December 2021 at Allison’s plant in Szentgotthárd, Hungary.