The 2008 Subaru Tribeca features dramatic exterior styling changes, reflecting the major changes under the skin for the 2008 Subaru Tribeca. A new 3.6-liter boxer engine has been designed with a goal of improving low-end torque and also lowering consumer running costs with a change to regular unleaded fuel. The larger engine displacement has increased engine torque to 247 lb.-ft., up from 215, and horsepower to 256 from 245, providing improved low-end torque without sacrificing high-rpm power. The new engine package, despite the larger engine size, not only maintains emissions levels but delivers improved fuel efficiency in real world driving situations. To achieve these goals without affecting engine packaging, a unique shortened con rod was created to allow for a new and larger displacement engine without increasing the physical dimensions of the power unit. Keeping the deck height of the engine the same, the Tribeca is able to maintain its excellent low center of gravity. Improved cooling efficiency – needed to achieve the use of regular fuel – was achieved through a new common rail cooling system that individually cools each cylinder with water separation chambers rather than allowing water to flow from cylinder to cylinder. This allows for increased engine efficiency and standardized timing for all cylinders. The new 3.6-liter engine features Active Valve Control System (AVCS) variable valve timing on both the intake and exhaust valves (the 3.0-liter engine had AVCS on the intake side only). The new 3.6-liter H6 engine is connected to a substantially revised 5-speed automatic transmission that features an all-new torque lock-up converter and a new transmission control unit that deliver faster shifts and quicker reaction time. The new transmission delivers smoother shifts with less lag time and weighs less than the previous system, for a total weight reduction of 9.7-lbs. for the new drivetrain.