General

GENERAL

To improve the dynamic performance and fuel efficiency of the vehicle, a new 5-speed automatic transmission is developed. The features of this new automatic transmission are as follows:

NEW CONSTRUCTION
- The planetary gears layout has been changed from the conventional 2-planetary to a 3-planetary arrangement.
- The construction of the torque converter has been changed to achieve a higher efficiency.
- The layout of the oil pump has been changed to reduce friction.
- The drive pinion gear has been changed.
- Major components are made of aluminum.

CHANGES FOR BETTER DRIVING PERFORMANCE

1. IMPROVED SHIFTING PERFORMANCE
- By using a wide ranged and crossed ratio gears, a high driving power is ensured at a wide vehicle speed range, and the torque differential between before and after shifting is minimized.
- By using a system that controls the clutch pressure directly and electronically (direct hydraulic control), an accurate and highly responsive control is achieved.
- By using a one-way clutch, smooth shifting without torque interruption is realized.
- By using a new adaptive control, the shifting map is automatically switched and a more active shifting control is performed in the manual mode.
- The control enables manual shifting by operating the steering switch to UP or DOWN while driving in D range, and returns to normal automatic shifting when certain conditions are met.
- To reduce gear noise from the reduction driven gear and prevent the bending moment of the drive pinion shaft from affecting the engagement of reduction gears, the front and rear ends are supported with bearings.
- To reduce driving noise, the drive shafts and joints are integrated and the transmission side drive axle shaft is abolished.

MODIFICATION MADE FOR BETTER FUEL EFFICIENCY

1. OPTIMIZED GEAR RATIO
- The wider gear ratio range obtained by five speeds contribute to better dynamic performance, while improving fuel efficiency at constant speed cruising by enabling use of lower engine speeds.

2. IMPROVED EFFICIENCY
- The efficiency of the torque converter has been increased.
- Friction in the oil pump and gear train are reduced.
- Drive pinion gear teeth are changed to uniform height teeth, and their offset amount is reduced.
- Ranges in which the transmission operates in slipping lockup and full lockup states are widened.

3. WEIGHT REDUCTION
- An aluminum bearing plate is used.
- The planetary carrier, clutch drum and the hub are made of aluminum.
- The wall thickness of the transmission case is reduced.

CONVENTIONAL MECHANISMS
- The transfer is provided with a VTD (Variable Torque Distribution) system which consists of a planetary gear type center differential and a hydraulic multi-plated LSD, to electronically control the differential operation and improve safety and drivability.