10 Apr 2018


The OF1621 model features an Allison T270 with a retarder for extending brake life – and significantly reducing maintenance costs. Mercedes-Benz Argentina and its official dealer COLCAR teamed up with Allison to develop this new bus for public transportation. The bus is equipped with a T270 fully automatic transmission,

Automatics use a torque converter to transfer engine power and torque to the wheels, requiring only periodic changes of fluid and filter for maximum performance. Manual transmissions and the automated manual transmissions (AMTs) depend on the clutch, which wears out over time and requires more downtime for its maintenance.

The hydraulic retarder on the T270 further reduces downtime by extending up to four times the life of the brakes. During development, the bus operated for Nueva Metropol on the route between Jose C. Paz and Saavedra. After 168,000 km, the bus rear brake linings still had 1.3 mm of braking material.

In order to cover that same distance, a bus with a manual transmission would have required the following maintenance: six exchanges of brake linings and two exchanges of brake bands for the rear brakes, two exchanges of clutches and five exchanges of lubricating oil.  

Considering all the structural, personnel, logistics and parts costs for a fleet, the maintenance between a bus equipped with a manual transmission versus a fully automatic transmission with a retarder is significant: the automatics generate annual savings of US $4,277 per unit, equalling $25,662 in six years – or more than $2.5 million for a fleet of 100 units. 

The bus is equipped with a Mercedes-Benz OM 924 LA engine, with 208 hp and maximum torque of 780 Nm, which complies with Euro V pollutant emission standards. Its electronic injection system ensures maximum performance with reduced fuel consumption and high torque at low laps. Allison Automatics are designed for reliability and durability, while helping protect the vehicle driveline. With Continuous Power Technology, drivers achieve faster acceleration, greater operational flexibility and increased productivity, Allison claims.

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