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Chrysler’s 9-speed

Model-year 2014 marks the debut of Chrysler Group’s nine-speed automatic transmission. (Earlier post.) The advanced-technology gearbox enables aggressive launches, smooth power delivery at highway speeds and greater fuel efficiency than a six-speed automatic transmission. Its ratios are:

  1. 4.71
  2. 2.84
  3. 1.91
  4. 1.38
  5. 1.00
  6. 0.81
  7. 0.70
  8. 0.58
  9. 0.48

The wide ratio spread delivers outstanding low-end performance while small gear-ratio steps contribute to smooth transitions. Four overdrive ratios benefit highway fuel economy and reduce overall noise, vibration and harshness (NVH) levels.

The fully electronic nine-speed automatic features on-the-fly shift map changing with manual-shifting capability via Electronic Range Select. More than 40 shift maps correspond to specific conditions to optimize shift quality and shift points for improved fuel economy, performance and drivability.

To determine the appropriate shift mode, the software accounts for variables such as engine torque gradients, kick-down events, longitudinal and lateral acceleration and grade changes. For improved driving comfort and refinement, additional parameters integrated into the transmission control strategy include: temperature, speed and electronic stability control. The result is automatic shifting attuned to the performance requirements of almost any driving situation.

Internally the transmission has four gear sets and six shift elements: multi-disc clutches, dog clutches and brakes. Only two friction-plate clutches are open in every gear, minimizing power loss.

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