The new size-class transmission is a result of extensive product development work done by Sandvik and the transmission supplier to meet the customer needs for 63t and 51t trucks.

With the new transmission, Sandvik TH663i and Sandvik TH551i trucks are expected to increase productivity and enable shorter cycle times. Maximum speed and efficiency in varying ramps and with different loads can be achieved with eight gears and optimised axle ratio, compared to the previous transmission with six gears.

According to Sandvik, the fully proportional, more powerful hydraulic retarder operates simultaneously with the engine brake, enabling easier downhill control and higher speeds. Further, lock-up to lock-up gear shifting can enable quick and smooth shifting and keep speed better while driving uphill.

The company added that improved reliability and reduced costs can be achieved with the new transmission's robust and simple design, made specifically for heavy off-road applications. Compared to the previous model, the transmission lifetime is expected to be longer, and fewer gearbox changeouts should be required during the truck lifetime, reducing total costs.

From the intelligence point of view, self-diagnostics in the transmission control system has been improved and fully integrated into the Sandvik Intelligent Control System, which can enable easy and fast troubleshooting without external diagnostics tools or laptops.

"We have tested the new transmission extensively in Finland, Ireland and Australia with our trucks in mine conditions," said Pia Sundberg, product line manager, trucks at Sandvik. "We are confident that this solution will significantly improve the truck performance and reliability.

"Also, it is great to say that based on the feedback we have received from our field tests with Sandvik TH663i, easy operation and extremely smooth gear shifting really make a difference and improve operator comfort significantly."

Other new features in the upgraded Sandvik TH663i and Sandvik TH551i trucks include a new durable and maintenance-friendly cooler with excellent corrosion resistance and long component lifetimes.

All new Sandvik TH663i and Sandvik TH551i trucks will be fitted with the new transmission as of early 2020, and it is also available as a retrofit to the trucks in the field.