General Description
GENERAL DESCRIPTIONThe automatic transmission consists of the hydraulic torque converter, electronically controlled 3-speed automatic transmission, countershaft and differential.
The transmission consists of 2 planetary gears, 2 disk clutches, 1 band brake, 1 disk brake and 1 one-way clutch. Its operation is controlled by selecting a position from 6 positions ("P", "R", "N", "D", "2" and "L") manually by means of the selector lever installed on the compartment floor.
In the "D" or "2" range, the gear ratio is changed for the 1st, 2nd or 3rd speed ("D" range only) automatically by transmission control module (electronic control).
For the automatic transmission fluid, DEXRON(R)-III or its equivalent must be used. Lubrication in the automatic transmission is provided by the oil pump which is operated by the engine revolution. Therefore, the engine should not be stopped even during coasting to obtain proper lubrication.
When it becomes necessary to be towed, front wheels must be raised so as not to roll them.
Torque Converter
The torque converter is of 3-element hydraulic type and consists of the pump, turbine and stator in a unit incapable of disassembly. The pump is mounted to the crankshaft (drive plate), the turbine to the input shaft and the stator to the transmission case (oil pump cover) by way of the one-way clutch.
The torque converter, which increases torque when starting, accelerating and up-hill driving, functions as a fluid clutch while driving at a constant speed.
Planetary Gear Units
In this unit, the sun gear is mounted in its center and engaged with it are 4 pinion gears supported by a carrier. Then, the outer ring gear is engaged with them. Depending on gear combinations, revolution is changed in speed or direction.
Among the units which operate in connection with the planetary gear unit, there are a direct clutch, a second brake, a forward clutch, a one-way clutch and a 1st-reverse brake.
Direct Clutch
The direct clutch connects the input shaft and the sun gear (common to both front and rear planetary gear units). It operates at the 3rd gear in the "D" range and in the "R" range. At the same time, the forward clutch operates in the former and the 1st-reverse brake in the latter.
Forward Clutch
The forward clutch connects the input shaft and ring gear of the front planetary gear. It operates in the ranges other than "P", "R" and "N". The units which operate simultaneously with the forward clutch are as follows.
- One-way clutch at the 1st gear in "D", "2" or "L".
- Second brake at the 2nd gear in "D", "2" or "L".
- Direct clutch at the 3rd gear in "D".
- 1st-reverse brake at the 1st gear in "L".
Second Brake
The second brake is of band type. It holds the sun gear of the front and rear planetary gear units stationary. It operates at the 2nd gear in "D", "2" or "L" simultaneously with the forward clutch.
First & Reverse Brake
The 1st-reverse brake holds the rear planetary carrier stationary. It operates in "L" or "R". At the same time, the forward clutch operates in "L" and the direct clutch in "R".
One-way Clutch
The sprag type one-way clutch is used between the rear planetary carrier and the transmission case. It consists of a one-way clutch race, sprags and a retainer, and the one-way clutch race is mounted to transmission case. When the rear planetary carrier is in motion to turn to in the arrow direction the first gear in "D", "2" or "L", the sprags stick between carrier and race, and prevent the planetary carrier from turning in the arrow direction.