02-4 AUTOMATIC TRANSMISSION () GENERAL 1. AUTOMATIC TRANSMISSION OVERVIEW DC 5-speed Automatic Transmission Assembly T-Tronic DC 5-speed automatic transmission is an electronically controlled 5-speed transmission with a lockup clutch in the torque converter. The ratios for the gears are realized by three planetary gear sets. The 5th gear is designed with a stepup ratio of 0.83 as an overdrive. The selector lever is controlled by electronically and mechanically. The gears are shifted by the corresponding combination of three hydraulically actuated multiple-disc brakes, three hydraulically actuated multiple-disc clutches and two mechanical oneway clutches. This electronically controlled automatic transmission adjusts the operating pressure to provide proper shifting in relation to engine power. This function improves shifting quality significantly. And, the driver can select "S" (Standard) mode or "W" (Winter) mode according to the driving conditions.
02-5 Instrument Panel TCU Assembly TCCU TCU Releasing Lock-up Solenoid Valve Standard Mode / Winter Mode When the gear selector lever cannot be moved from "P" position to other positions, manually release the lock-up function as shown in figure. "S" mode is used in normal driving. When "W" mode is selected, the vehicle starts from 2nd gear (forward and reverse) to achieve smooth starting on the slippery road. Selector Lever Downshift (Manual Mode) 1 2 3 4 D The shiftable gear is down by one step as the lever is moved to left (-) direction. Upshift (Manual Mode) 1 2 3 4 D The shiftable gear is up by one step as the lever is moved to right (+) direction.
02-6 2. AUTOMATIC TRANSMISSION () APPEARANCE Left Side With Torque Converter Without Torque Converter Rear View
02-7 3. AUTOMATIC TRANSMISSION STRUCTURE This sectional drawing is based on DC 5-speed A/T 2WD model. 4WD model has also same structure. 1. Torque converter 2. Oil pump 3. Input shaft 4. Disc brake B1 5. Disc clutch C1 6. Disc clutch C2 7. Disc brake B3 8. Disc clutch C3 9. Disc brake B2 10. Output shaft 11. Parking lock gear 12. Intermediate shaft 13. Freewheel F2 14. Center planetary gear set 15. Electric control unit (valve body) 16. Freewheel F1 (Front planetary gear set) 17. Stator shaft 18. Converter lockup clutch
02-8 Specifications
02-9
02-10 Characteristics of Automatic Transmission - Performance Curve D20DT Standard Mode WINTER Mode (2WD) Lockup Mode (Open/Slipping) Upshift: Downshift: Lockup (slipping): Unlock (open): FAST OFF: Dynamic shift zone: FAST OFF: When abruptly releasing the accelerator pedal, the transmission remains at 4th gear other than 4 5 shift (when slowly releasing the accelerator pedal, the transmission is shifted to 5th gear). Dynamic shift zone: When operating the accelerator pedal (B), the 4 3 shift is completed by kick-down signal after completion of 4 3 shift (100% of pedal position). When promptly operating the accelerator pedal (C), the 4 3 shift is done in shaded area (93% of pedal position). 4th gear: 1.000 5th gear: 0.833 Rev. 1st gear: 3.147 Rev. 2nd gear: 1.93 Low Mode (4WD)
02-11 D27DT Standard Mode Lockup Mode (Open/Slipping) Upshift: Downshift: Lockup (slipping): Unlock (open): FAST OFF: Dynamic shift zone: FAST OFF: When abruptly releasing the accelerator pedal, the transmission remains at 4th gear other than 4 5 shift (when slowly releasing the accelerator pedal, the transmission is shifted to 5th gear). Dynamic shift zone: When operating the accelerator pedal (B), the 4 3 shift is completed by kick-down signal after completion of 4 3 shift (100% of pedal position). When promptly operating the accelerator pedal (C), the 4 3 shift is done in shaded area (93% of pedal position). 4th gear: 1.000 5th gear: 0.833 Rev. 1st gear: 3.147 Rev. 2nd gear: 1.93 WINTER Mode
02-12 General Characteristics
02-13 OVERVIEW AND OPERATION PROCESS 1. POWER FLOW Brake B1(disk) assembly Brake B3 (disk) assembly Brake B2 (disk) assembly C1 (Disk clutch) assembly C2 (Disk clutch) assembly C3 (Disk clutch) assembly
02-14 Shifting Elements 1) Selector program switch: S mode 2) Selector program switch: W mode 3) Overrun
02-15 1) 1st Gear (D20DT: 3.951, D27DT: 3.595) 16. Torque converter lockup clutch A. Engine speed B. Transmission, input shaft C. 1st gear ratio D. 2nd gear ratio E. 3rd gear ratio F. Locking elements H. Rear planetary gear set L. Stator M. Center planetary gear set P. Impeller T. Turbine wheel V. Front planetary gear set 1. Input shaft: Clockwise rotation 2. Front sun gear: Locked by F1 and B1, Planetary gear carrier: Rotation with reduced speed 3. Rear ring gear: clockwise rotation 4. Rear sun gear: Locked by F2 and B2, Planetary gear carrier: Clockwise rotation with reduced speed 5. Center ring gear: Clockwise rotation 6. Center sun gear: Locked by B2, Rotation with reduced speed 7. Output shaft: Clockwise rotation 3) Overrun
02-16 2) 2nd Gear (D20DT: 2.423, D27DT: 2.186) 16. Torque converter lockup clutch A. Engine speed B. Transmission, input shaft C. 1st gear ratio D. 2nd gear ratio E. Locking elements H. Rear planetary gear set L. Stator M. Center planetary gear set P. Impeller T. Turbine wheel V. Front planetary gear set 1. Input shaft: Clockwise rotation 2. Sun gear and planetary gear carrier: Clockwise rotation by C1 activation 3. Rear ring gear: Clockwise rotation 4. Rear sun gear: Locked by F2 and B2, Planetary gear carrier: Rotation with reduced speed 5. Center ring gear: Clockwise rotation 6. Sun gear: Locked by B2, Planetary gear carrier: Rotation with reduced speed 7. Output shaft: Clockwise rotation 3) Overrun
02-17 3) 3rd Gear (D20DT: 1.486, D27DT: 1.405) 16. Torque converter lockup clutch A. Engine speed B. Transmission, input shaft C. 1st gear ratio D. Locking elements H. Rear planetary gear set L. Stator M. Center planetary gear set P. Impeller T. Turbine wheel V. Front planetary gear set 1. Input shaft: Clockwise rotation 2. Front ring gear: Clockwise rotation 3. Center ring gear: Clockwise rotation by clutch 2 activation (direct connection) 4. Center sun gear: Locked by B2, Planetary gear carrier: Clockwise rotation with reduced speed 5. Output shaft: Clockwise rotation
02-18 4) 4th Gear (1.000) 16. Torque converter lockup clutch A. Engine speed B. Planetary gear set L. Stator M. Center planetary gear set P. Impeller T. Turbine wheel V. Front planetary gear set 1. Input shaft: Clockwise rotation 2. Front ring gear: Clockwise rotation 3. Center ring gear and rear planetary gear carrier: Clockwise rotation 4. Front sun gear and planetary gear carrier: Clockwise rotation (direct connection) 5. Rear ring gear: Clockwise rotation 6. Rear sun gear: Rotation by ring gear and planetary gear carrier (direct connection) 7. Center sun gear: Clockwise rotation by C3 activation 8. Planetary gear carrier: Clockwise rotation by center sun gear and ring gear (direct connection) 9. Output shaft: Clockwise rotation
02-19 5) 5th Gear (D20DT: 0.833, D27DT: 0.831) 16. Torque converter lockup clutch A. Engine speed B. Transmission, input shaft C. 1st gear ratio D. 2nd gear ratio E. 3rd gear ratio F. Locking elements H. Rear planetary gear set L. Stator M. Center planetary gear set P. Impeller T. Turbine wheel V. Front planetary gear set 1. Input shaft: Clockwise rotation 2. Front sun gear: Locked by B1, Planetary gear carrier: Rotation with reduced speed 3. Rear planetary gear ring gear: Clockwise rotation with reduced speed 4. Center ring gear and rear planetary gear carrier: Clockwise rotation by clutch C2 activation 5. Rear sun gear: Clockwise rotation because rear planetary gear carrier rotates faster than rear ring gear(increased speed) 6. Center sun gear: Clockwise rotation with increased speed by clutch C3 activation 7. Center planetary gear carrier: Clockwise rotation (increased speed) 8. Output shaft: Clockwise rotation (increased speed) 3) Overrun
02-20 6) Reverse 1st Gear (D20DT: 3.147, D27DT: 3.167) - Standard (S) Mode 16. Torque converter lockup clutch A. Engine speed B. Transmission, input shaft C. 1st gear ratio D. 2nd gear ratio E. Locking elements F. Locking elements H. Rear planetary gear set L. Stator M. Center planetary gear set P. Impeller T. Turbine wheel V. Front planetary gear set 1. Input shaft: Clockwise rotation 2. Front ring gear: Clockwise rotation 3. Front sun gear: Locked by one-way clutch F1 4. Front planetary gear carrier: Clockwise rotation (reduced speed) 5. Rear planetary gear ring gear: Clockwise rotation 6. Rear planetary gear carrier: Locked by B3 7. Rear sun gear and center sun gear: Counterclockwise rotation (increased speed) 8. Center ring gear: Locked by B3 9. Center planetary gear carrier: Counterclockwise rotation (reduced speed) 10. Output shaft: Counterclockwise rotation 3) Overrun
02-21 7) Reverse 2nd Gear (D20DT: 1.93, D27DT: 1.926) - Winter (W) Mode Mode 16. Torque converter lockup clutch A. Engine speed B. Transmission, input shaft C. 1st gear ratio D. 2nd gear ratio E. Locking elements H. Rear planetary gear set L. Stator M. Center planetary gear set P. Impeller T. Turbine wheel V. Front planetary gear set 1. Input shaft: Clockwise rotation 2. Front ring gear: Clockwise rotation 3. Front planetary gear carrier: Clockwise rotation by clutch C1 activation (direct connection) 4. Rear ring gear: Clockwise rotation 5. Rear planetary gear carrier and center ring gear: Locked by brake B3 6. Rear sun gear and center sun gear: Counterclockwise rotation (increased speed) 7. Center planetary gear carrier: Counterclockwise rotation (reduced speed) 8. Output shaft: Counterclockwise rotation