Chrysler introduces new eight-speed automatic transmission

Beginning this Fall with the 2012 model year, Chrysler 300s and Dodge Chargers equipped with the 3.6-litre Pentastar VVT V6 engine, will also come with a new eight-speed automatic transmission, the first eight-speed automatic available in a domestically-produced vehicle.

The Chrysler 300 and Dodge Charger are built in Brampton, Ontario.

The new 845RE transmission is manufactured by German transmission specialist ZF and is similar to eight-speed transmissions developed by ZF for a variety of Audi, BMW, Bentley, Range Rover and Rolls Royce models. The transmission will be supplied initially by ZF, but in the future, Chrysler will build the transmission itself in its Kokomo, Indiana transmission plant.

Once domestic production of the transmission is underway, it is expected that the 845RE will replace the current five-speed transmission in most applications, including V8s. The current five-speed is an older Mercedes-Benz designed transmission.

Why eight speeds? Fuel economy is the primary reason. With the 845RE, highway fuel consumption for both the Chrysler 300 and Dodge Charger with rear-wheel drive improves from 7.3 L/100 km to 6.4 L/100 km, a 16 per cent improvement.

Energuide rates the two for city driving at 10.9 litres per 100 km – an increase of eight per cent in fuel economy over the five-speed automatic. With eight speeds, driving at a lower rpm in both city and highway environments also effectively helps reduce emissions by nearly 11 per cent on both vehicles.

The 845RE is also available with all-wheel drive models. Energuide ratings for the AWD models are not yet available, but will certainly be better than the outgoing 2011 models.

The 845RE is a fully electronic transmission with software that provides optimal “adaptive” shifting characteristics. Adaptive shifting takes into account a number of variables including engine torque gradients, kick down, longitudinal and lateral acceleration, hill detection, friction detection and downshift detection in determining shift patterns. Additional parameters include vehicle speed control, electronic stability control activation and high temperatures that can affect transmission shifting.

We had the opportunity earlier this summer to drive an early 2012 Chrysler 300 prototype at Chrysler’s proving grounds in Chelsea, Michigan. We noted that the 300 benefited from nearly imperceptible gear changes due in part to very evenly spaced gear steps between each gear ratio. The gear steps also are very small providing quicker acceleration and smoother shifts.

High efforts in shifting also have been eliminated with gear selection controlled by a shift-by-wire system. The position selected by the driver (P, R, N, D) is transmitted electronically with no mechanical linkage from the shifter to the outside of the transmission. Elimination of this linkage removes any shift effort from the driver’s gear selection.

During spirited driving, sporty, quick shifts are possible as a result of multiple parameters through a “Sport” shift mode. At the rear of the shifter is a gate that allows for down- and up-shifting by the driver. Once the vehicle is in the “Sport” mode, the driver can use either the console-mounted shifter or a pair of paddle controls located on the steering wheel.

Acceleration times provided by Chrysler for the Dodge Charger and Chrysler 300 for 0 to 100 km/h are 7.2 seconds.

Lower viscosity transmission fluid is used resulting in improved transmission efficiency and fuel economy improvements especially during cold environments or vehicle start-up. The 845RE also has a “fill for life,” not requiring oil changes during normal driving conditions.

The 845RE transmission will be standard equipment on all V6-powered 2012 Chrysler 300 and Dodge Charger models with the exception of the entry-level Chrysler 300 Touring and Dodge Charger SE models, for which it will be optionally available.

Article and photos by Grant Yoxon
Autos.ca