|David Brown and Santasalo
|Transmission & Drives
This fully automatic transmission has been developed under contract to the UK MoD, to be interchangeable with the TN37 transmission installed in the Challenger 1 MBT. The TN54 is now in production for the Challenger Armoured Repair and Recovery Vehicle and for the Challenger 2 MBT which are now in service with Qatar and the UK.
The TN54 has a single input and two in-line outputs at right angles to the input. Drive is transmitted from the engine through a splined coupling to a torque converter. The gear and direction of travel are engaged by correctly sequenced application of multiplate clutches, actuated hydraulically and controlled by electro-solenoid valves. The TN54 transmission features six forward and two reverse gears, a hydrostatic double-differential steering system and integral oil-cooled multiplate main vehicle and parking brakes.
The transmission has integral filtered lubrication and hydraulic systems. A Power Take-Off (PTO) for power pack cooling fans is mounted on top of the main casing.
Alternatively the transmission is supplied with a mechanical steer unit incorporating controlled slip multiplate clutches.
TN54 is also available to suit transversely mounted engines and in this designation it is known as the TN54U.
This has been developed as a private venture and is an uprated version of the TN54.
In production for Challenger Armoured Repair and Recovery Vehicle and Challenger 2 MBT. In service with Oman and the UK. By mid-1999, over 450 TN54 transmissions had been built.