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Home >> Volvo >> 2007 >> S40 Base, 2.4 38, Automatic >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Miscellaneous Components - Design And Function (544 Body) >> Transmission (M56; 2004-2010) >> Function >> Power Flow
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Power Flow

The torque of the engine is transferred from the clutch to the input shaft and then onwards via different gear sets and driving final drives, depending on the gear selected, to the final drive/differential, drive shafts and out to the front wheels.

1st gear 

Fig 1: Identifying Power Flow 1st Gear
GLL139984Courtesy of VOLVO CARS OF NORTH AMERICA.
Number Designation Number Designation
B Lower output (secondary) shaft 5 1st speed gear
1 Input shaft 11 1st gear idler wheel /back-up (reverse) intermediate gear
2 Final drive 12 Coupling sleeve for 1st and 2nd gear
4 Driving final drive    

When 1st gear is selected, the coupling sleeve for 1st-2nd gear is moved by a gear selector fork along the synchronizing hub towards the idler wheel for 1st gear. The coupling sleeve and synchronizing hub lock the idler wheel for 1st gear at the lower output (secondary) shaft.

The engine torque is transferred from the clutch to the input shaft to the gear and idler wheel for 1st gear, through the lower output (secondary) shaft and on to the final drive gear and out to the final drive.

2nd gear 

Fig 2: Identifying Power Flow 2nd Gear
GLL139985Courtesy of VOLVO CARS OF NORTH AMERICA.
Number Designation Number Designation
B Lower output (secondary) shaft 6 2nd speed gear
1 Input shaft 12 Coupling sleeve for 1st and 2nd gear
2 Final drive 13 2nd gear idler wheel
4 Driving final drive    

When 2nd gear is selected, the coupling sleeve for 1st-2nd gear is moved by a gear selector fork along the synchronizing hub towards the idler wheel for 2nd gear. The coupling sleeve and synchronizing hub lock the idler wheel for 2nd gear at the lower output (secondary) shaft.

The engine torque is transferred from the clutch to the input shaft to the gear and idler wheel for 2nd gear, through the lower output (secondary) shaft and on to the final drive gear and out to the final drive.

3rd gear 

Fig 3: Identifying Power Flow 3rd Gear
GLL139986Courtesy of VOLVO CARS OF NORTH AMERICA.
Number Designation Number Designation
A Primary shaft 4 Driving final drive
B Lower output (secondary) shaft 9 Coupling sleeve for 3rd and 4th gear
1 Input shaft 10 3rd gear idler wheel
2 Final drive 15 3rd speed gear

When 3rd gear is selected, the coupling sleeve for 3rd/4th gear is moved by a gear selector fork along the synchronizing hub towards the idler wheel for 3rd gear. The coupling sleeve and synchronizing hub lock the idler wheel for 3rd gear at the primary shaft.

The engine torque is transferred from the clutch to the input shaft, to the idler wheel for 3rd gear. It is then transferred to the gear for 3rd gear on the lower output (secondary) shaft, and on to the final drive gear and out to the final drive.

4th gear 

Fig 4: Identifying Power Flow 4th Gear
GLL139987Courtesy of VOLVO CARS OF NORTH AMERICA.
Number Designation Number Designation
A Primary shaft 4 Driving final drive
B Lower output (secondary) shaft 8 4th gear idler wheel
1 Input shaft 9 Coupling sleeve for 3rd and 4th gear
2 Final drive 14 4th speed gear

When 4th gear is selected, the coupling sleeve for 3rd/4th gear is moved by a gear selector fork along the synchronizing hub towards the idler wheel for 4th gear. The coupling sleeve and synchronizing hub lock the idler wheel for 4th gear at the primary shaft.

The engine torque is transferred from the clutch to the input shaft, to the idler wheel for 4th gear. It is then transferred to the gear for 4th gear on the lower output (secondary) shaft, and on to the final drive gear and out to the final drive.

5th gear 

Fig 5: Identifying Power Flow 5th Gear
GLL139988Courtesy of VOLVO CARS OF NORTH AMERICA.
Number Designation Number Designation
A Primary shaft 7 5th speed gear
C Upper output (secondary) shaft 17 Coupling sleeve for 5th/back-up (reverse) gear
2 Final drive 18 5th gear idler wheel
3 Driving final drive    

When 5th gear is selected, the coupling sleeve for 5th/back-up (reverse) gear is moved by a gear selector fork along the synchronizing hub towards the idler wheel for 5th gear. The coupling sleeve and synchronizing hub lock the idler wheel for 5th gear at the upper output (secondary) shaft.

The engine torque is transferred from the clutch to the input shaft, to the gear on the primary shaft for the idler wheel for 5th gear on the upper output (secondary) shaft, and on to the final drive gear and out to the final drive.

Back-up (reverse) gear 

Fig 6: Identifying Power Flow Back-up (Reverse) Gear
GLL139989Courtesy of VOLVO CARS OF NORTH AMERICA.
Number Designation Number Designation
B Lower output (secondary) shaft 9 Coupling sleeve for 3rd and 4th gear
C Upper output (secondary) shaft 11 1st gear idler wheel /back-up (reverse) intermediate gear
1 Input shaft 16 Idler wheel for back-up (reverse) gear
2 Final drive 17 Coupling sleeve for 5th/back-up (reverse) gear
3 Driving final drive 20 Synchronizing relay
5 1st speed gear    

When back-up (reverse) gear is selected, the coupling sleeve for 5th/back-up (reverse) gear is moved by a gear selector fork along the synchronizing hub towards the idler wheel for back-up (reverse). The coupling sleeve and synchronizing hub then lock the idler wheel for back-up (reverse) at the upper output (secondary) shaft.

The engine torque is transferred from the clutch to the input shaft, to the gear on the primary shaft for the idler wheel for 1st gear (which also acts as intermediate gear for back-up (reverse) gear) on the lower output (secondary) shaft. It is then transferred to the idler wheel for back-up (reverse) gear on the upper output (secondary) shaft, and on to the final drive gear and out to the final drive.

Because the idler wheel for 1st gear is used as the intermediate gear for back-up (reverse) gear, there is no separate shaft for back-up (reverse) gear.