All-New 2005 Jeep Grand Cherokee

Press Release

Engines

Among the many firsts in the 2005 model year for Jeep Grand Cherokee are two engines�the 3.7-liter SOHC V-6 and 5.7-liter HEMI V-8 and two five-speed automatic transmissions.

5.7-Liter HEMI V-8

The modern HEMI has been engineered to deliver outstanding performance and reduced noise, vibration and harshness (NVH), resulting in a highly refined powerplant. The engine gives the Grand Cherokee best-in-class power and 90 percent of the engine’s peak torque is available from 2,400 through 5,100 rpm for excellent performance. The engine produces 325 horsepower (242 kW)at 5,100 rpm and 370 lb.-ft. (502 N•m) at 3,600 rpm.

“Two legends combine with the introduction of the modern HEMI V-8 in the 2005 Jeep Grand Cherokee,� said Eric Ridenour, Executive Vice President�Product Development. “The HEMI is the most powerful engine ever offered in a Grand Cherokee and easily gives the vehicle best-in-class power.�

Fuel economy has also been improved, but not at the expense of HEMI performance. Chrysler Group has developed the Multi-Displacement System (MDS) that deactivates four cylinders when the V-8 is not needed. The 2005 Grand Cherokee is the first SUV to offer fuel-conserving MDS.

The Chrysler Group MDS seamlessly alternates between smooth and economic four-cylinder mode when less power is needed and V-8 mode when more power from the 5.7-liter HEMI engine is in demand. This optimizes fuel economy when V-8 power is not needed without sacrificing vehicle performance or towing capability.

“The MDS was part of the engine’s original design,� said Bob Lee, Vice President�Powertrain Product Team. “This results in a cylinder deactivation system that is elegantly simple and completely integrated into the engine design. The benefits are fewer parts, maximum reliability and lower cost.�

Some of the significant technologies enabling the MDS are the speed of electronic controls, the sophistication of the algorithms controlling the systems and the use of Electronic Throttle Control. The HEMI is able to transition from eight cylinders to four in 40 milliseconds. This engine and MDS has completed over 6.5 million customer-equivalent miles through Chrysler Group’s development and durability testing. It is covered by the seven-year/70,000-mile Limited Powertrain warranty.

The HEMI engine that powers the 2005 Jeep Grand Cherokee uses aluminum cylinder heads with hemispherical combustion chambers, creating outstanding airflow leading to high power and torque. Dual ignition (two spark plugs per cylinder) increases peak power and torque, reduces exhaust emissions, increases fuel economy and provides a smooth idle. The combustion system has been refined and the engine uses direct-mount accessories for quieter operation.

4.7-Liter, SOHC V-8 Engine

The 4.7-liter V-8 has been updated and is now the mid-range engine in Grand Cherokee. The engine produces 230 hp (172 kW) at 4,700 rpm and 290 lb.-ft. (393 N•m) of torque at 3,700 rpm. Dual knock sensors have been added for 2005 and enable improved engine calibration for both fuel economy and power output.

The engine has improved NVH characteristics, which were realized through the use of composite valve covers, structural improvements to the air box and resonator and improved dampening of the heat shields.

3.7-Liter, SOHC V-6 Engine

The 3.7-liter V-6 engine provides the 2005 Jeep Grand Cherokee with an efficient, durable and smooth base engine. It produces 210 hp (157 kW) at 5200 rpm and 235 lb.-ft. (319 N•m) at 4000 rpm. The 3.7-liter, SOHC V-6 will replace and deliver even more peak power than the previous 4.0-liter I-6 in the Jeep Grand Cherokee lineup. The engine was first introduced in the Jeep Liberty and has been continuously refined to provide smooth V-6 power with optimal economy.

Significant changes in the 3.7-liter include a revised cam profile and new valve lash adjusters. These changes improve the engine smoothness at idle. To ensure quiet operation, a thick-wall composite manifold is new for 2005, as are structural improvements to the air box and resonator.

Five-Speed Automatic Transmissions

An all-new five-speed automatic transmission offers smooth shifts and optimum fuel economy with the 3.7-liter V-6. The 545RFE five-speed automatic has been refined for higher-quality shifts while increasing the Grand Cherokee’s maximum towing capacity.

The all-new five-speed has an Electronically Modulated Converter Clutch, which is electronically modulated and provides partial engagement in third, fourth or fifth gears. This results in improved shift feel, fuel economy, driveability and transmission cooling. It can be used at lower speeds to provide benefits over a broad speed range. The system unlocks the torque converter when optimal performance is required.

The shift schedule for the five-speed used in V-6 applications adapts to individual driving style, driving situation and road conditions, altering shift points based on accelerator pedal usage, brake usage, lateral acceleration, altitude and load on the car as a result of grades. An electronically controlled engine Torque Management System provides quick wide-open-throttle upshifts and quick two-step (4-2 or 3-1) kick-down shifts that are exceptionally smooth.

The 545RFE five-speed transmission has been refined to offer smoother operation and better economy while improving the performance and towing capability of the vehicle.

To accomplish this, several features were added, including a redesigned solenoid to provide quieter operation when shifting from “park� into “drive.� A turbine damper also improves NVH related to torque converter application.

The 545RFE continues to offer dual second-gear ratios to provide a balance of performance and fuel economy. Depending on driving conditions, the transmission will select the more appropriate second gear. A secondary overdrive ratio increases highway fuel economy and reduces engine noise at high speeds.

Quadra-Trac® I

For Jeep Grand Cherokee customers who want the assurance of full-time all-wheel drive and no switches or levers to pull, Quadra-Trac® I is the right system. The system provides for smooth operation of the vehicle over a variety of road surface conditions.

The new NV140 transfer case splits torque 48/52 percent (front/rear) for nearly even distribution of the engine power. The single-speed transfer case has been designed to rigorous Jeep durability standards while offering smooth and quiet operation. The use of Brake Traction Control System (BTCS) with the NV140 transfer case makes the 4x4 system extremely competent in a variety of situations.