Main Components and Functions
Main Components and FunctionsTorque Converter
The torque converter is a four element device that transmits and multiplies torque. The four elements are the impeller, turbine, reactor and the clutch/damper assembly. A torque converter operates as follows:
- Rotation of the converter housing and impeller set the fluid in motion.
- The turbine reacts to the fluid motion from the impeller, transferring rotation to the geartrain through the input shaft.
- The reactor redirects fluid back into the impeller, providing for torque multiplication.
- The clutch and damper assembly dampens powertrain torsional vibration and provides a direct mechanical connection for improved efficiency.
- Power is transmitted from the torque converter to the planetary gearsets and other components through the input shaft.
Geartrain
Planetary Gearset
The transaxle has two planetary gearsets to provide operation in reverse and four forward speeds. A front sun gear, front carrier, rear ring gear, front ring gear/rear carrier and a rear sun gear are the main components of the planetary gear set.
Turbine Shaft
The turbine shaft is splined to both the torque converter stator and the DRIVE sprocket. This allows input torque to be transmitted from the torque converter to the transaxle.
Idler Gear
The idler gear is driven by the output shaft and is attached to the reduction gear. The reduction gear drives the final DRIVE ring gears, which are part of the differential. The idler gear also provides a gear for the parking pawl to lock the final DRIVE from rotating.
Reduction Gear
The reduction gear connects the output shaft to the final DRIVE ring gear and provides gear reduction.
Differential Assembly
The differential assembly drives the front wheel driveshaft and joints and allows the front wheel driveshaft and joints to turn at different speeds.
Apply Components
2-4 Band
The 2-4 band is used to shift the transaxle into second and fourth gear (O/D). It is operated by the 2-4 servo. The 2-4 band holds the primary sun gear stationary by locking it to the transaxle case.
Forward Clutch
The forward clutch is applied in all forward gears. The forward clutch connects the input shaft to the ring gear through the forward one-way clutch (sprag).
Coasting Clutch
The coasting clutch is applied in all forward gears only when the overdrive (O/D) control switch is off. The coasting clutch connects the input shaft to the ring gear, bypassing the forward one-way clutch. The coasting clutch allows for engine braking upon deceleration.
Low/Reverse Clutch
The low/reverse clutch is applied in manual low first gear and reverse gears only. The low/reverse clutch holds the front planet stationary by locking it to the transaxle case.
3-4 Clutch
The 3-4 clutch is applied in third and fourth gears only. The 3-4 clutch drives the front planet directly from the input shaft.
Low One-Way Clutch
The low one-way clutch is engaged in first gear, with the exception of manual low. In manual low, the low one-way clutch is locked out by the application of the low/reverse clutch. The low one-way clutch prevents the front planet from rotating counter-clockwise. The low one-way clutch overruns during deceleration in first gear, with the exception of manual low.
Forward One-Way Clutch
The forward one-way clutch is engaged in all forward gears during acceleration. The forward one-way clutch overruns during deceleration. The forward one-way clutch connects the forward clutch to the ring gear during acceleration.
Hydraulic System
Fluid Pump
The fluid pump provides a supply of transmission fluid under pressure to operate, lubricate, and cool the transaxle. The oil pump is a trochoid gear positive displacement pump with output flow proportional to demand. The oil pump is mounted to the transaxle case.
Main Controls
The main control valve body directs fluid under pressure to the torque converter, band servos and clutches. A system of valves, passages and check balls are used to direct fluid to the necessary component. The solenoid assembly is used to operate various valves in the valve body in order to control transaxle shift timing, feel and schedule.
1-2 Accumulator
The 1-2 accumulator cushions the application of a friction component during a 1-2 upshift. The 1-2 accumulator is located within the upper control valve body.
N-D Accumulator
The N-D accumulator cushions the engagement of the forward clutch when the transaxle is shifted from NEUTRAL (N) to DRIVE (D). The N-D accumulator is located the main control valve body.
D-R Accumulator
The D-R accumulator cushions the engagement of the Reverse Clutch when the transaxle is shifted from DRIVE (D) to REVERSE (R). The D-R accumulator is located in the main control valve body.