Jeep Cherokee 2014
Chrysler Group
The introductions, which span multiple model lines, send a clear message to the world.
“We are steadfast in our commitment to innovate for the benefit of our customers,” said Mircea Gradu, Vice President — Powertrain Transmission and Driveline Engineering and Head of Virtual Analysis. “Nowhere is this more evident than on the all-new 2014 Jeep® Cherokee.”
The all-new Cherokee’s stylish appearance belies the rugged capability delivered by its unique 4x4 system.
It is the first mid-size sport-utility (SUV) to feature a front-wheel-drive-based rear-axle disconnect system. It delivers four-wheel traction whenever it’s needed, without driver intervention.
A fully variable wet clutch housed in the rear drive module supplies the proper amount of torque for any traction condition. This capability also is a boon to aggressive starts.
Sophisticated algorithms enable the system to benefit driving dynamics by interacting with electronic stability control (ESC). When conditions are more favorable, it seamlessly switches to two-wheel-drive for optimum efficiency.
The system is available with either a one- or two-speed driveline (PTU and RDM). A locking differential is available with the two-speed PTU.
In low range, the 2.92:1 gear reduction also sets up aggressive crawl ratios – 56:1 when the vehicle is powered by the 2.4-liter Tigershark I-4 engine, and 47.8:1 when powered by the new 3.2-liter Pentastar V-6. Such specifications benefit off-road performance.
An available locking rear differential enhances control in extreme off-road conditions and is selectable in any low-range terrain mode.
Geared up
Model-year 2014 also marks the world debut of Chrysler Group’s nine-speed automatic transmission.
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:
1st – 4.71
2nd – 2.84
3rd – 1.91
4th – 1.38
5th – 1.00
6th – 0.81
7th – 0.70
8th – 0.58
9th – 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 all-new, 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 sophisticated 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.
Other new transmissions are the AS66RC six-speed automatic featured in 2014 Ram chassis cab models, and the M40 six-speed automated manual in the all-new Ram ProMaster full-size commercial van.
Sourced from Aisin, the AS66RC allows for optional 45HP and 250 lb.-ft. left- or right-side PTO. Paired with the HEMI®, efficiency is improved with Fuel Saver cylinder deactivation operation while in PTO mode.
The new M40 automated manual is mated to the 3.0-liter EcoDiesel I-4 in the ProMaster. The unique gearbox delivers the efficiency of a manual transmission with the functionality of an automatic.
At its core, it is a manual, but gearshifts and clutch functions are accomplished with an electro-hydraulic actuation system.
However, the driver can opt for manual shift-lever inputs when desired. But the driver needn’t do all the work. Shift logic is adjusted according to grade steepness so the gearbox responds intuitively to driving conditions.