1995 Chrysler Corporation Drivetrain Changes
The information in this file was provided by Chrysler Corporation. Changes were described in the 318 V8, 3.5 liter V6, and the automatic transmissions.
5.2 SMPI V-8 (Grand Cherokee)
A revised camshaft had broadened the torque curve of the 5.2-liter engine, providing up to 30 lb.-more torque below 3200 rpm. Peak torque of 289 lb.-ft, 15-lb.-ft more than with the previous camshaft, was reached at 3200 rpm, 400 rpm less than with the previous cam. Peak power remained at 220 horsepower but the rated speed was 4400 rpm, 400 rpm lower than the previous rating point. The dynamics of the camshaft also reduced valve train noise. The broader torque curve provided 3 percent better acceleration over the first 5 seconds and a better launch feel. It also increased gradability by 8 percent in overdrive (Fourth gear) and 7 percent in direct drive (Third gear).
3.5 Liter Engine (LH series only)
The 3.5 liter SOHC 24 valve engine was extensively modified to meet "Tier 1" emission control requirements and improve part throttle fuel economy. To maintain previous high levels of power and torque while increasing fuel economy and meeting the new requirements the following refinements were added:
* Grafal (R) coating on piston skirts to reduce friction at high speed * Intake ports redesigned to increase air flow capacity * Larger water pump pulley to reduce flow rate, optimizing cooling system performance and reducing parasitic drag at high speed
To improve driveability and speed control performance, the throttle cams had a progressive action, providing slower response to input during low- speed and cruising speed than before. This helped avoid a feeling of "jumpiness" and maintained more consistent speed with speed control in operation.
See also 3.5 Liter SOHC 24 valve Engine Emission Control Systems for LHS, New Yorker, Concorde, Intrepid and Vision under Protecting The Atmosphere in the Environmental section.
42LE Electronic Four-Speed Overdrive Automatic (LH only)
The chain and sprocket drive system, which transmitted drive from the transmission output shaft to the final drive transfer shaft pinion gear, was refined for quieter operation. Two single-row chains replaced the dual-row chain used previously. The teeth of the two sprockets had an angular offset of 1/2-pitch so that the sound of chain-to-sprocket engagement was reduced and made more uniform. The new chain system was stronger, lighter and more compact than its predecessor. The material for the snubber that reduced noise by restricting chain free play was upgraded from plastic to rubber.
For easier access and reading, the transmission fluid dipstick and housing were lengthened by 2 in. (50 mm) and the stick rotated 180 degrees relative to the handle. The handle was yellow with black nomenclature for easier location.
See also Underhood Maintenance and Inspection Points for Concorde, LHS, New Yorker, Intrepid and Vision under Serviceability & Maintenance.
41 TE Electronic 4-speed Overdrive Automatic - LeBaron Convertible, minivans
An automatic speed control overspeed reduction feature was added to the transmission control software. It helped maintain vehicle speed at the selected set point when descending a grade. The TCM (transmission control module) first sensed that the speed control was set. If the set speed was exceeded by more than 4 mph (6.5 km/hr) and the throttle was closed, the TCM caused the transaxle to downshift to Third gear. Subsequent to the downshift, the automatic speed control continued its normal operation. To assure that an upshift was appropriate after the set speed was reached, the TCM waited until the throttle was opened at least 8 degrees by the speed control system before upshifting to Overdrive again. If the driver applied the brakes, canceling automatic speed control operation with the transaxle still in Third gear, the TCM maintained this gear until the driver opened the throttle at least 8 degrees to avoid an inappropriate upshift. The upshift was also delayed for 0.5 seconds after reaching the 8 degree throttle opening in anticipation that the driver might open the throttle enough to require Third gear, thus avoiding unnecessary and disturbing cycling of the transmission. If the automatic speed control RESUME feature was used after braking, the upshift was delayed until the set speed was achieved to reduce cycling and provide better response.
Additional refinements continued on the 41TE electronic four-speed automatic transaxle. For 1995, software changes provided smoother 2-1 low speed, heavy throttle downshifts. Kick-down shifts after a coast- down in Third were also refined.
31TH 3-speed Automatic (minivans, Spirit/Acclaim)
A lower helix angle in the transfer gear set reduced noise. An increase in the helix angle from 27.5 degrees to 32 degrees made the gears quieter by placing more teeth in simultaneous contact.
30RH 3-speed Automatic for Cherokee Four-Cylinders
Cherokee offered an optional automatic transmission-model 30RH-with the 2.5L OHV SMPI four-cylinder engine in 1995. Features of the transmission included three-speeds and a computer-controlled lockup torque converter that reduced engine noise at highway speeds and enhanced highway fuel economy. Ratios were: 2.45, 1.45 and 1.00 as in other Chrysler-built 3-speed automatic transmissions. Internal components were sized to the four-cylinder Cherokee's power and weight.