Challenger Terra Gator 3244 Chassis. Manual - part 26

 

  Index      Challenger     Challenger Terra Gator 3244 Chassis - service repair manual 2009 year

 

Search            

 

 

 

 

 

 

 

  

 

Content   ..  24  25  26  27   ..

 

 

Challenger Terra Gator 3244 Chassis. Manual - part 26

 

 

627333-A  

3-17

Transmission and Solenoids

Partial Signal Current  (Modulation)

Modulating Valve

1. Modulating Valve;

2. Test Port;

3. Clutch;

4. Spring;

5. Line to Sump;

6. Spool Orifice;

7. Charge Pressure Oil;

8. To Transmission Clutch;

9. Solenoid;

10. Ball;

11. Valve Spool;

12. Drain Orifice;

13. Pin;

14. Charge Pressure;

15. Sump;

16. 1st Charge Pressure Reduction.

The transmission ECM controls the signal current in

order to modulate the flow of oil through modulating

valve (1). When solenoid (9) receives less than

maximum programmed signal current, the flow is

modulated.

Oil Flow in Valve with less than Maximum Signal 

Current

The engagement of transmission clutch (3) begins when

the transmission ECM initially sends signal current in

order to energize the solenoid.

The signal current creates a magnetic field around pin

(13) which will cause the pin to move to the right against

ball (10).

The force against the ball will be in proportion to the

strength of the signal current from the transmission

ECM.

The position of the ball against drain orifice (12) restrict

the oil flow to sump (5). This partial restriction causes the

pressure at the left end of valve spool (11) to increase.

The oil pressure moves the valve spool to the right

against spring (4). The movement of the valve spool

starts to open a passage on the right end of the valve

spool. As a result, charge pressure oil (7) will start to fill

the transmission clutch. Oil also begins to fill the

chamber for the spring on the right end of the valve

spool.

In the initial stage for filling the transmission clutch with

oil, the transmission ECM sends a high pulse of current

in order to quickly move the valve spool.

During this short period of time, the clutch piston will

move in order to remove the clearances that are

between the clutch discs and the plates. This will

minimize the amount of time that is needed to fill the

clutch.

The transmission ECM will then reduce the signal

current which also reduce the pressure setting of the

modulating valve. The change in signal current reduces

the flow of oil to the transmission clutch.

When the plates and the discs start to touch each other,

this is called the touch-up point. Once the touch-up point

is obtained, the transmission ECM begins a controlled

increase of the signal current in order to start the

modulation cycle.

FIG. 17

Q000041S

10

9

13

12

5

8

7

4

11

2

1

6

14

15

16

Transmission and Solenoids

3-18

627333-A  

The increase in the signal current causes the ball and

pin to further restrict the flow of oil through the drain

orifice and to the sump. This causes a controlled

movement of the valve spool to the right.

This movement of the valve spool allows the pressure

to transmission clutch (3) to increase.

The modulating valve uses the variable signal current

from the transmission ECM to vary the pressure output

of the valve.

The sequence of partial engagement is called desired

slippage. The clutches must slip a specific amount in

order to provide smooth shifting. The desired slippage

is controlled by the application program that is stored in

the transmission ECM.

627333-A  

3-19

Transmission and Solenoids

Maximum Signal Current (Clutch Fully Engaged)

Modulating Valve

1. Modulating Valve;

2. Test Port;

3. Clutch;

4. Spring;

5. Line to Sump;

6. Spool Orifice;

7. Charge Pressure Oil;

8. To Transmission Clutch;

9. Solenoid;

10. Ball;

11. Valve Spool;

12. Drain Orifice;

13. Pin;

14. Charge Pressure;

15. Sump;

When the modulation  cycle stops, the transmission

ECM will send the maximum specified signal current in

order to fully engage the transmission.

The constant signal current pushes pin (11) firmly

against ball (10) in modulating valve (1).

The force against the ball reduces the amount of oil flow

through drain orifice (12). This restriction causes an

increase in pressure on the left side of valve spool (13).

The valve spool moves to the right to allow the charge oil

to fully engage the transmission clutch.

In a short period of time, maximum pressure is felt at

both ends of the valve spool. This pressure and the

additional force that is produced by spring (4) causes the

valve spool to move to the left until the forces on the right

end and the left end of the valve spool are balanced.

The movement of the valve spool to the left balanced

position reduces the flow of oil to the engaged

transmission clutch. The transmission ECM sends a

constant maximum specified signal current to solenoid

(8) in order to maintain the desired clutch pressure.

FIG. 18

Q000042S

10

6

1

2

13

4

7

3

5

12

11

8

14

15

3-20

627333-A  

Transmission and Solenoids

TRANSMISSION CLUTCH ENGAGEMENT

Side view of transmission

1. Input Shaft

2. Gear;

3. Gear;

4. Gear;

5. Gear;

6. Gear;

7. Intermediate Shaft;

8. Gear;

9. Gear;

10. Gear;

11. Gear;

12. Gear;

13. Output Shaft;

14. Planetary Carrier;

15. Gear;

16. Gear;

17. Planetary Carries

18. Transfer Gear shaft;

A - B. Planetary Carries

C - H. Clutch Pack 

FIG. 19

Q000044S

C

D

E

F

B

G

H

A

1

2

3

4

5

6

12

9

8

7

10

11

14

15

16

17

18

13

 

 

 

 

 

 

 

Content   ..  24  25  26  27   ..