Page 25 of 3502

A/T CONTROL SYSTEM
AT-17
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B
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Shift MechanismBCS000ZO
CONSTRUCTION
FUNCTION OF CLUTCH AND BRAKE
1. Torque converter 2. Oil pump 3. Input shaft
4. Brake band 5. Reverse clutch 6. High clutch
7. Front sun gear 8. Front pinion gear 9. Front internal gear
10. Front planetary carrier 11. Rear sun gear 12. Rear pinion gear
13. Rear internal gear 14. Rear planetary carrier 15. Forward clutch
16. Forward one-way clutch 17. Overrun clutch 18. Low one-way clutch
19. Low & reverse brake 20. Parking pawl 21. Parking gear
22. Output shaft 23. Idler gear 24. Output gear
SAT998I
Clutch and brake components Abbr. Function
5Reverse clutch R/C To transmit input power to front sun gear 7 .
6High clutch H/C To transmit input power to front planetary carrier 10 .
15Forward clutch F/C To connect front planetary carrier 10 with forward one-way clutch 16 .
17Overrun clutch O/C To connect front planetary carrier 10 with rear internal gear 13 .
4Brake band B/B To lock front sun gear 7 .
16Forward one-way clutch F/O.CWhen forward clutch 15 is engaged, to stop rear internal gear 13 from rotating
in opposite direction against engine revolution.
18Low one-way clutch L/O.CTo stop front planetary carrier 10 from rotating in opposite direction against
engine revolution.
19Low & reverse brake L & R/B To lock front planetary carrier 10 .
Page 26 of 3502

AT-18
A/T CONTROL SYSTEM
CLUTCH AND BAND CHART
*1: Oil pressure is applied to both 2nd “apply” side and 3rd “release” side of band servo piston. However, brake band does not con-
tract because oil pressure area on the “release” side is greater than that on the “apply” side.
*2: Oil pressure is applied to 4th “apply” side in condition *1 above, and brake band contracts.
: Operates.
A: Operates when throttle opening is less than 3/16, activating engine brake.
B: Operates during “progressive” acceleration.
C: Operates but does not affect power transmission.
D: Operates when throttle opening is less than 3/16, but does not affect engine brake. Shift posi-
tionR/C
5H/C
6F/C
15O/C
17Band servo
F/O.C
16L/O.C
18L&R/B
19Lock-
upRemarks
2nd
apply3rd
release4th
apply
PPA R K
POSITION
RREVERSE
POSITION
NNEUTRAL
POSITION
1st D B B
D2nd A BAutomatic
shift
3rd A *1C C B1 ⇔ 2 ⇔ 3
⇔ 4
4th C *2C C
31st D B B
Automatic
shift
1 ⇔ 2 ⇔ 3 2nd A B
3rd A *1C C B
21stBB
Automatic
shift
1 ⇔ 2 ⇐ 3 2ndB
3rd *1C C B
11stBB
Locks (held
stationary)
in 1st speed
1 ⇐ 2 ⇐ 3 2ndB
3rd *1C C B
Page 27 of 3502
A/T CONTROL SYSTEM
AT-19
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POWER TRANSMISSION
“N” and “P” Positions
“N” position
Power from the input shaft is not transmitted to the output shaft because the clutches do not operate.
“P” position
Similar to the “N” position, the clutches do not operate. The parking pawl engages with the parking gear to
mechanically hold the output shaft so that the power train is locked.
SAT991I
Page 28 of 3502
AT-20
A/T CONTROL SYSTEM
“11 ” Position
Forward one-way clutch
Forward clutch
Overrun clutch
Low & reverse brakeAs overrun clutch engages, rear internal gear is locked by the operation of low and
reverse brake.
This is different from that of D
1 , 31 and 21 .
Engine brake Overrun clutch always engages, therefore engine brake can be obtained when deceler-
ating.
SCIA7863E
Page 29 of 3502
A/T CONTROL SYSTEM
AT-21
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“D1 ”, “31 ” and “21 ” Positions
Forward one-way clutch
Forward clutch
Low one-way clutchRear internal gear is locked to rotate counterclockwise because of the functioning of
these three clutches.
Overrun clutch
engagement conditions
(Engine brake)D
1 and 31 : Throttle opening is less than 3/16
2
1 : Always engaged
At D
1 , 31 and 21 positions, engine brake is not activated due to free turning of low
one- way clutch.
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Page 30 of 3502
AT-22
A/T CONTROL SYSTEM
“D2 ”, “32 ”, “22 ” and “12 ” Positions
Forward clutch
Forward one-way
clutch
Brake bandRear sun gear drives rear planetary carrier and combined front internal gear. Front internal gear now
rotates around front sun gear accompanying front planetary carrier.
As front planetary carrier transfers the power to rear internal gear through forward clutch and forward one-
way clutch, this rotation of rear internal gear increases the speed of rear planetary carrier compared with
that of the 1st speed.
Overrun clutch
engagement conditionsD
2 and 32 : Throttle opening is less than 3/16
2
2 and 12 : Always engaged
SCIA7865E
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A/T CONTROL SYSTEM
AT-23
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“D3 ”, “33 ”, “23 ” and “13 ” Positions
High clutch
Forward clutch
Forward one-way
clutchInput power is transmitted to front planetary carrier through high clutch. And front planetary carrier is con-
nected to rear internal gear by operation of forward clutch and forward one-way clutch.
This rear internal gear rotation and another input (the rear sun gear) accompany rear planetary carrier to
turn at the same speed.
Overrun clutch
engagement conditionsD
3 and 33 : Throttle opening is less than 3/16
2
3 and 13 : Always engaged
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Page 32 of 3502
AT-24
A/T CONTROL SYSTEM
“D4 ” Position
High clutch
Brake band
Forward clutch (Does not affect power
transmission)Input power is transmitted to front carrier through high clutch.
This front carrier turns around the sun gear which is fixed by brake band and makes
front internal gear (output) turn faster.
Engine brakeAt D
4 position, there is no one-way clutch in the power transmission line and engine
brake can be obtained when decelerating.
SCIA7867E