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Power Flow During Forward Travel, Function - GF27.10-P-3035ANR

Transmission 725.0 (except 725.096) in model 257, 290 

up to model year 2021 

Function requirements for power flow in forward travel, general 

Power flow, general 

The term "power flow" refers to the transmission paths of driving power and engine torques. The engine torques are transmitted to the drive wheels via the mechanical-hydraulic connection between the combustion engine, torque converter, the downstream automatic transmission and differential. Power is transferred in the torque converter via the driven impeller by diverting hydraulic fluid to the turbine wheel which is connected to the drive shaft. When the torque converter lockup clutch is engaged, power is transmitted via this mechanical connection. The gear wheels of the individual planetary gear sets forward the torques generated by the torque converter to the output shaft with the help of the multidisk clutches and multidisk brakes to match the transmission ratio and actuated shift elements. A reduction of the output speed in the low gears provides lower vehicle speeds with high tractive forces and increased drive torques at the drive wheels.

IMPORTANT All planetary gear sets consist of the following elements: sun gear, planetary gears, planet carrier and annulus gear.

Power flow characteristic curve 

The function sequence is described in the following steps:

G14549146Courtesy of MERCEDES-BENZ USA

Shown here is power flow in 1st gear 

Power flow function sequence, 1st gear 

The following multidisk brakes and multidisk clutches are engaged:

In 1st gear, the power flows through the following gear sets:

The sun gear of the planetary gear set P1 is part of the drive shaft and is driven by it. The planet carrier of the planetary gear set P1 is connected through the multiplate clutch K38 (E) to the ring gear of the planetary gear set P2. The multidisk brake B05 (B) brakes the sun gear of the planetary gear set P2. As a result, the torque increases and the rotational speed is decreased. The ring gear of the planetary gear set P2 has a mechanical connection to the sun gear of the planetary gear set P3. The planetary gears rotate in the ring gear of the planetary gear set P3 braked by the multidisk brake B06 (C) and the planet carrier of the planetary gear set P3 transfers the resulting increased torque and reduced rotational speed to the output shaft. The output shaft thereby rotates with a reduced input speed in the engine's rotation direction.

G14549147Courtesy of MERCEDES-BENZ USA

Shown here is power flow in 2nd gear 

Power flow function sequence, 2nd gear 

The following multidisk brakes and multidisk clutches are engaged:

In 2nd gear, the power flows through the following gear sets:

The sun gear of the planetary gear set P1 is part of the drive shaft and is driven by it. The multiplate clutch K81 (D) connects the drive shaft to the planet carrier of the planetary gear set P1 so that these revolve in the block. The multiplate clutch K38 (E) makes a mechanical connection to the sun gear of the planetary gear set P3. The multidisk brake B06 (C) brakes the ring gear of the planetary gear set P3. The planet carrier of the planetary gear set P3 transfers the resulting increased torque and reduced speed to the output shaft. The output shaft thereby rotates with a reduced input speed in the engine's rotation direction.

G14549148Courtesy of MERCEDES-BENZ USA

Shown here is power flow in 3rd gear 

Power flow function sequence, 3rd gear 

The following multidisk brakes and multidisk clutches are engaged:

In 3rd gear, the power flows through the following gear sets:

The sun gear of the planetary gear set P1 is part of the drive shaft and is driven by it. The multiplate clutch K81 (D) connects the drive shaft to the planet carrier of the planetary gear set P1 so that these revolve in the block. The ring gear of planetary gear set P1 is driven by the planet carrier of planetary gear set P1. In turn, the ring gear drives the planet carrier of the planetary gear set P2. The multidisk brake B05 (B) brakes the sun gear of the planetary gear set P2. Consequently, power is transmitted to the sun gear of the planetary gear set P3 through the ring gear of the planetary gear set P2. The multidisk brake B06 (C) brakes the ring gear of the planetary gear set P3. The planet carrier of the planetary gear set P3 transfers the resulting increased torque and reduced speed to the output shaft. The output shaft thereby rotates with a reduced input speed in the engine's rotation direction.

G14549149Courtesy of MERCEDES-BENZ USA

Shown: Power flow in 4th gear 

Function sequence for power flow, 4th gear 

The following multidisk brakes and multidisk clutches are engaged:

In 4th gear, the power flow flows through the following gear sets:

The sun gear of the planetary gear set P1 is part of the drive shaft and is driven by it. The planet carrier of the planetary gear set P4 is also driven. The sun gear of the planetary gear set P2 is braked by the multidisk brake B05 (B). The ring gear of the planetary gear set P2 supports the sun gears of the planetary gear sets P3 and P4. The multidisk brake B06 (C) brakes the ring gear of the planetary gear set P3. The multiplate clutch K27 (F) is closed and the planetary gear set P4 is switched in. The ring gear of the planetary gear set P3 and the ring gear of the planetary gear set P4 transfer the resulting increased torque and reduced rotational speed to the output shaft. The output shaft thereby rotates with a reduced input speed in the engine's rotation direction.

G14549150Courtesy of MERCEDES-BENZ USA

Shown: Power flow in 5th gear 

Function sequence for power flow, 5th gear 

The following multidisk brakes and multidisk clutches are engaged:

In 5th gear, the power flow flows through the following gear sets:

The sun gear of the planetary gear set P1 is part of the drive shaft and is driven by it. The planet carrier of the planetary gear set P4 is also driven by the drive shaft. The multiplate clutch K81 (D) connects the drive shaft to the planet carrier of the planetary gear set P1 so that these revolve in the block. The ring gear of planetary gear set P1 supports the planet carrier of planetary gear set P2. The multidisk brake B05 (B) brakes the sun gear of planetary gear set P2. As a result, the ring gear of planetary gear set P2 transfers the power to the sun gear of the planetary gear set P4. Via the closed multiplate clutch K27 (F), the ring gear of planetary gear set P4 transfers the resulting increased torque and reduced rotational speed to the output shaft. The output shaft thereby rotates with a reduced input speed in the engine's rotation direction.

Shown: Power flow in 6th gear 

G14549151Courtesy of MERCEDES-BENZ USA

Function sequence for power flow, 6th gear 

The following multidisk clutches are engaged:

In 6th gear, the power flow flows through the following gear sets:

The planet carrier of the planetary gear set P4 is driven by the drive shaft. The multiplate clutches K81 (D) andK38 (E) connect the respective elements of the planetary gear sets P1 and P2. As a result, these revolve in the block and support the sun gear of the planetary gear set P4. The closed multiplate clutch K27 (F) enables the ring gear of the planetary gear set P4 to transfer the torque to the output shaft. The output shaft rotates with the input speed in the of engine's rotation direction.

Shown: Power flow in 7th gear 

G14549152Courtesy of MERCEDES-BENZ USA

Power flow function sequence, 7th gear 

The following multidisk brakes and multidisk clutches are engaged:

In 7th gear, the power flow flows through the following gear sets:

The sun gear of the planetary gear set P1 is part of the drive shaft and is driven by it. The planet carrier of the planetary gear set P4 is also driven by the drive shaft. The ring gear of planetary gear set P1 supports the planet carrier of planetary gear set P2. The ring gear of planetary gear set P1 is driven by the planet carrier of the planetary gear set P1. The multidisk brake B05 (B) brakes the sun gear of the planetary gear set P2. As a result, the ring gear of the planetary gear set P2 transfers the power via the closed multiplate clutch K38 (E) to the sun gear of the planetary gear set P4. Via the closed multiplate clutch K27 (F), the ring gear of the planetary gear set P4 transfers the resulting reduced torque and increased rotational speed to the output shaft. The output shaft thereby rotates with an increased input speed in the engine's rotation direction.

Shown: Power flow in 8th gear 

G14549153Courtesy of MERCEDES-BENZ USA

Power flow function sequence, 8th gear 

The following multidisk brakes and multidisk clutches are engaged:

In 8th gear, the power flows via the following gear sets:

The sun gear of the planetary gear set P1 is part of the drive shaft and is driven by it. The planet carrier of the planetary gear set P4 is also driven by the drive shaft. The planet carrier of the planetary gear set P1 is braked by actuation of the multidisk brake B08 (A). The sun gear of the planetary gear set P4 is connected to the planet carrier of the planetary gear set P1 through actuation of the multiplate clutch K38 (E) and also braked. Via the closed multiplate clutch K27 (F), the ring gear of the planetary gear set P4 transfers the resulting reduced torque and increased rotational speed to the output shaft. The output shaft thereby rotates with an increased input speed in the engine's rotation direction.

Shown here is power flow in 9th gear 

G14549154Courtesy of MERCEDES-BENZ USA

Power flow function sequence, 9th gear 

The following multidisk brakes and multidisk clutches are engaged:

In 9th gear, the power flows through the following gear sets:

The sun gear of the planetary gear set P1 is part of the drive shaft and is driven by it. The planet carrier of the planetary gear set P4 is also driven by the drive shaft. The planet carrier of the planetary gear set P1 is braked by actuation of the multidisk brake B08 (A). The power flow runs via the ring gear of the planetary gear set P1 to the planet carrier of the planetary gear set P2. The multidisk brake B05 (B) brakes the sun gear of the planetary gear set P2. The ring gear of the planetary gear set P2 drives the sun gear of the planetary gear set P4. Via the closed multiplate clutch K27 (F), the ring gear of the planetary gear set P4 transfers the resulting reduced torque and increased rotational speed to the output shaft. The output shaft thereby rotates with an increased input speed in the engine's rotation direction.

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