Although 8-speed transmissions have been available for a while in some of the premium European brands, this is the first time one has been offered by a domestic automaker – and in vehicles costing thousands less.
Initially, the transmissions will be supplied by ZF (or ZF Friedreichshafen AG engineering in Germany) – the same company that produces gearboxes for Audi and BMW – but Chrysler has obtained rights and licensing to eventually produce them in-house.
For now, the 8-speed will only be available in the V6 rear-wheel drive platforms, and while nobody at Chrysler would confirm that a version bolted to V8 engines was in the works at the time of our drive, they didn't deny it, either. With that familiar, enigmatic industry smile, they would only concede that it could be "V8 compatible".
Fuel economy was the number one priority in the 8-speed transmission's (or 845RE) development – it reportedly delivers 10.9 L/100km averaged between the two models, a "double-digit improvement" over current fuel numbers.
"No other component in the driveline can provide that kind of fuel improvement" said Head of Transmission and Driveline Engineering, Mircea Gradu. Part of that is attributed to its compact size; the new transmission is lighter than the 6-speed it replaces, and at only 80 kegs, is only marginally heavier than the 5-speed.
Second in importance was comfort – more gears and smaller gear steps result in transitions that are almost imperceptible.
So, what was it like?
We drove both rear- and all-wheel drive 300 sedans and Chargers on a two-lane "ride road" composed of various aggregates, and a tight little test track where we were able to really open the cars up and evaluate the new gearbox's ability.
Suffice it to say, if you're familiar with any of the German vehicles packing the ZF 8-speed transmission, you might find the 845RE's performance remarkably similar. It's no slushbox.
Gear transitions are nearly seamless during regular driving, and the low rpm range helps reduce fuel consumption at cruising speed. It's no slug though; with the extra gear sets, the 8-speed can quickly put power to the ground when asked. The 845RE is equipped with "adaptive shifting" software that calculates temperature, gradient, longitudinal and lateral acceleration, hill detection, friction detection… and modifies its gear changing accordingly to best suit the situation.
Selecting Sport mode tightens up the shifts and wakes up the Pentastar V6 by keeping the rpms in the engine's power band. The response is quick and lively – particularly noticeable in the 300 which was more engaging on the track than with its previous gearbox.
The idea of an 8-speed gearbox must have resonated with buyers, since the pre-order books for vehicles so equipped has already closed due to high demand. The push is on for Chrysler to finish its Kokomo, Indiana Plant sooner than the projected 2013 opening date.
