Top dog in the Tundra line is the available i-FORCE MAX hybrid powertrain with 437 horsepower at 5,200 rpm, and a staggering 583 lb.-ft. of torque at a low 2,400 rpm. Yet, this new powerhouse is also an efficiency maven, with up to EPA-estimated 20 MPG city/24 MPG highway/22 MPG combined fuel economy ratings, depending on model grade and drivetrain. The new i-FORCE MAX combines the twin-turbo V6 with a motor generator with a clutch located within the bell housing between the engine and 10-speed automatic transmission. The motor generator provides additional power through the transmission, while the engine start-up, EV driving, electric assist and energy regeneration are solely done via the parallel hybrid components. The system employs a proven and reliable 288V sealed Nickel-metal Hydride (Ni-MH) battery located under the rear passenger seats.