T25 Skid Steer Transmission

Developed from an original design by Borg Warner this skid steer transmission brings purpose-designed, fully independently sided skid steer capability into the 21st century with increased power and torque capacity, elimination of a variety of failure modes, slicker gear change and improved IO options.

The T25 sits at the heart of Maximus, but can be supplied in a variety of configurations including the T21 which is suitable for use in Max vehicles, benefiting from all-new T25 internals but with an external form factor identical to the veteran T20. Bespoke versions can also be made available for special purposes.

T20 – some background

The T20 steering box was originally designed for use with lightweight 6×6 vehicles; its useful life is substantially shortened in bigger, heavier and more powerful vehicles and when exposed to additional loadings associated with 8×8 use. This made the existing T20 design a non-starter for production-quality 8×8 machines capable of moving 6 or more personnel and substantial loads.

A detailed and fundamental design review was required. The challenge set and subsequently met was to support substantially more demanding usage profiles, within the same space envelope at similar or lower cost.

We partnered with leading transmission system designers and manufactures to develop our enhanced family of transmission steering boxes, building upon the Max T20 heritage.

We will shortly introduce our new improved range, these boxes will offer higher power and torque capacities, improving upon the overall strength of the original T20 design and addressing some of the long-standing usability issues.

The range will include 3 new and substantially enhanced steering box variants designed to suit both legacy and future generation vehicles:

  • The T20 version will be gently retired by us for new-vehicle builds, however we will continue to offer it for use in other lightweight skid-steer applications and will continue to provide parts and service support.
  • T21 – externally this is exactly the same shape and size as the current generation T20, internally it has all the features of the new range. It is designed to be a direct replacement for T20 boxes.
  • T22 – the same input shaft as the T20 and T21 but with duplex output sprockets, better suited to transfer of the additional torque and power that the box can now handle.
  • T25 – the same casing and control layout with duplex output sprockets and including a longer, stronger and more robust input shaft which is compatible with a wider range of modern continuously variable transmission clutches.

The enhanced range of boxes address long running issues with the T20 such as difficult gear change. Difficulty in changing gear has been a major constraint in realising the full functionality of the box – making split shift control impractical during routine use and denying the additional manoeuvrability that has been part of the basic design for more than 40 years. With smoother and more consistent gear change on the T21-25 ranges, split shift operation becomes not only possible but straightforward. The clever design is at last able to achieve its full potential.

We will also be breaking with long-held tradition. Versions of the box will be made available for use in other products, subject to strict qualification conditions. A wide user base with more diverse challenges will spin off dynamic and innovative design; this first major step in product development will not be the last. 

These boxes will become available for use in Q4 2019.

Part sales, whole transmissions, chains & accessories direct and through our US partner.