Upgraded powertrain extends military vehicle's operational life

The introduction of a new engine and the latest fully automatic transmission technology has seen a military vehicle produced by Engesa that was a success in the 80s and 90s back in front line action.

Considered by many to be out of action - as the last units were, for many years, parked in the battalion storage of the Brazilian Army - the armoured Engesa EE-11 Urutu may yet be ready for service again. Destined for troop transportation, the EE-11 despite weighing 13 tons, is a highly capable amphibious vehicle. Together with its carrying capacity, these features made the Urutu very popular among many national armies in South America. With a new powertrain, it is set to strike again.

Its name was taken from the venomous Urutu snake, from the family of Veperidae, the same as the rattlesnake, the bushmaster and Jararaca - the three feared reptiles of the South American forests. The Urutu's attributes and importance to the Brazilian Army led the local force to decide to reactivate 226 units and more than 600 armoured Cascavel (or rattlesnake) vehicles. All of those were mothballed and in storage. With a very old-fashioned powertrain, and a mix of manual and automatic gearboxes, Urutu and Cascavel had a sizeable technological disadvantage during operations. The Brazilian Army believed that by updating the powertrain of their armoured vehicles, they could keep them running for the next 15 years. That claim was validated after a rigorous evaluation made with a prototype produced by those involved in the project.

For the first prototype the existing Mercedes-Benz OM 352 engine was replaced by a militarized OM 366 LA, increasing the power output from 158hp to 230hp. Coupled to the Engesa transfer box, the original Mercedes G3-36 gearbox was changed for an up to date Allison 3000SP automatic transmission, with electronic controls. The initial tests on light terrain saw the prototype reach a top speed of 110km/h. Over heavier off-road situations, the vehicle could travel at 80km/h. Crucially, the range was increased from 750km to 950km.

Engemotors, a company of the Brasília Motors group is undertaking the upgrade. According to Glauco Bueno da Silva, general manager for Engemotors, one of the reasons for using Allison's automatic gearboxes on all the Urutu and Cascavel units is the improved drivability. "In a combat vehicle during battle, it is difficult for the driver to focus on the gear change coordination, clutch usage, choosing the best gear for each situation and so on. With an automatic transmission the driver is free from such distractions and so they can concentrate on the mission. The Allison 3000SP gearbox we now use is more resistant and delivered very interesting results during the tests. The performance is superior to old versions equipped with manual/automatic transmissions as that older transmission generation, when used in the Urutu, had no electronic management and lacked many updates which help vehicles to have better serviceability".

Source: Allison Transmission