992G Wheel Loader and 854G Wheel Dozer Power Train Transmission Planetary Caterpillar


Transmission Planetary
`
1.1. First Speed Forward
2.1. Second Speed Forward
3.1. Third Speed Forward
4.1. Third Speed Reverse
5.1. Second Speed Reverse
6.1. First Speed Reverse



Illustration 1g00104723

Transmission Components

(1) Coupling gear. (2) Number 1 clutch. (3) Number 2 and Number 3 carrier. (4) Number 2 clutch. (5) Number 2 clutch ring gear. (6) Number 2 sun gear. (7) Number 3 clutch. (8) Number 3 clutch ring gear. (9) Number 3 sun gear. (10) Number 4 clutch. (11) Number 4 clutch ring gear. (12) Number 4 sun gear. (13) Number 5 clutch. (14) Rotating hub. (15) Number 4 carrier. (16) Number 1 carrier. (17) Number 1 sun gear. (18) Input shaft. (19) Number 1 planetary gears. (20) Number 1 clutch ring gear. (21) Number 2 planetary gears. (22) Number 3 planetary gears. (23) Number 4 planetary gears. (24) Output shaft.

The transmission is fastened between the input transfer gear case and the output transfer gear case. Input power to the transmission comes from the input transfer gears.

The transmission has five hydraulically activated clutches that provide three forward speeds and three reverse speeds. Speed and direction are selected by moving switches on the STIC. The Number 1 clutch and the Number 2 clutch are the closest clutches to the input end of the transmission. These two clutches are the direction clutches. The Number 1 clutch is the Reverse direction clutch. The Number 2 clutch is the Forward direction clutch.

The Number 3 clutch, the Number 4 clutch, and the Number 5 clutch are the speed clutches. The Number 3 clutch provides the Third speed. The Number 4 clutch provides the Second speed. The Number 5 clutch provides the First speed.

The Number 5 clutch is the only clutch that rotates when the clutch is engaged.

A speed clutch must be engaged first and a direction clutch must then be engaged so that power may be sent through the transmission. The table provides the combination of the clutches for each forward speed and for each reverse speed.

Table 1
Speed Range and Direction     Energized Solenoids     Engaged Clutches    
Third Speed Forward     3 and 2     3 and 2    
Second Speed Forward     4 and 2     4 and 2    
First Speed Forward     5 and 2     5 and 2    
Neutral     3     3    
First Speed Reverse     5 and 1     5 and 1    
Second Speed Reverse     4 and 1     4 and 1    
Third Speed Reverse     3 and 1     3 and 1    

First Speed Forward




Illustration 2g00106974

Power Flow in First Speed Forward with the Number 2 Clutch and the Number 5 Clutch Engaged.

(3) Number 2 and Number 3 carrier. (4) Number 2 clutch. (5) Number 2 clutch ring gear. (6) Number 2 sun gear. (8) Number 3 clutch ring gear. (9) Number 3 sun gear. (11) Number 4 clutch ring gear. (12) Number 4 sun gear. (13) Number 5 clutch. (14) Rotating Hub. (15) Number 4 carrier. (18) Input shaft. (21) Number 2 planetary gears. (22) Number 3 planetary gears. (24) Output shaft.

When the transmission is in first speed forward, Number 5 clutch (13) and Number 2 clutch (4) are engaged. The Number 2 clutch holds ring gear (5) stationary. The Number 5 clutch connects rotating hub (14) to Number 4 carrier (15) .

Input shaft (18) turns Number 2 sun gear (6). The Number 2 sun gear turns planetary gears (21). Because ring gear (5) is held stationary by the Number 2 clutch, planetary gears (21) move around the inside of the ring gear. The movement of planetary gears (21) causes Number 2 carrier (3) and Number 3 carrier (3) to turn in the same direction as input shaft (18) .

As carrier (3) turns, planetary gears (22) turn ring gear (8) and sun gear (9). Sun gear (9) turns output shaft (24) .

Ring gear (8) turns carrier (15). Carrier (15) is connected to rotating hub (14) by the engagement of Number 5 clutch (13). This allows power to travel from carrier (15) to sun gear (12) and to ring gear (11). The power then travels through Number 5 clutch to rotating hub (14). Sun gear (12) and rotating hub (14) are fastened to output shaft (24) .

As a result, the torque to output shaft (24) is divided between Number 3 sun gear (9), Number 4 sun gear (12), and rotating hub (14). From the output shaft, power travels through the output transfer gears to the differentials.

Second Speed Forward




Illustration 3g00104764

Power Flow in Second Speed Forward with the Number 2 Clutch and the Number 4 Clutch Engaged.

(3) Number 2 and Number 3 carrier. (4) Number 2 clutch. (5) Number 2 clutch ring gear. (6) Number 2 sun gear. (8) Number 3 clutch ring gear. (9) Number 3 sun gear. (10) Number 4 clutch. (11) Number 4 clutch ring gear. (12) Number 4 sun gear. (15) Number 4 carrier. (18) Input shaft. (21) Number 2 planetary gears. (22) Number 3 planetary gears. (23) Number 4 planetary gears. (24) Output shaft.

When the transmission is in second speed forward, Number 4 clutch (10) and Number 2 clutch (4) are engaged. The Number 2 clutch holds ring gear (5) for the Number 2 clutch stationary. The Number 4 clutch holds ring gear (11) for the Number 4 clutch stationary. Input shaft (18) turns Number 2 sun gear (6). Number 2 sun gear turns Number 2 planetary gears (21) .

Because ring gear (5) is held stationary by the Number 2 clutch, planetary gears (21) move around the inside of the ring gear. The movement of planetary gears (21) causes Number 2 carrier (3) and Number 3 carrier (3) to turn in the same direction as input shaft (18). As the Number 2 carrier and the Number 3 carrier turn, Number 3 planetary gears (22) turn. The Number 2 planetary gears turn ring gear (8) for the Number 3 clutch and Number 3 sun gear (9). Number 3 sun gear (9) turns output shaft (24). Ring gear (8) turns Number 4 carrier (15) .

Because ring gear (11) is held stationary by the Number 4 clutch, planetary gears (23) move around the inside of the ring gear. The movement of planetary gears (23) causes Number 4 sun gear (12) to turn. The Number 4 sun gear turns output shaft (24) .

As a result, the torque to output shaft (24) is divided between Number 3 sun gear (9) and Number 4 sun gear (12). From the output shaft, power travels through the output transfer gears to the differentials.

Third Speed Forward

Refer to illustration 1 for the location of the components, as described below. Refer to illustration 2 for a typical description of power flow in the forward direction.

When the transmission is in third speed forward, Number 3 clutch (7) and Number 2 clutch (4) are engaged. The Number 2 clutch holds ring gear (5) for the Number 2 clutch stationary. The Number 3 clutch holds ring gear (8) for the Number 3 clutch stationary. Input shaft (18) turns Number 2 sun gear (6). Number 2 sun gear turns Number 2 planetary gears (21) .

Because ring gear (5) is held stationary by the Number 2 clutch, planetary gears (21) move around the inside of the ring gear. The movement of planetary gears (21) causes Number 2 carrier (3) and Number 3 carrier (3) to turn in the same direction as input shaft (18) .

The movement of Number 2 carrier (3) and Number 3 carrier (3) causes Number 3 planetary gears (22) to move around the inside of ring gear (8) because ring gear (8) is held stationary by the Number 3 clutch. The movement of planetary gears (22) causes Number 3 sun gear (9) to turn. The Number 3 sun gear turns output shaft (24). From the output shaft, power travels through the output transfer gears to the differentials.

Third Speed Reverse




Illustration 4g00104767

Power Flow in Third Speed Reverse with the Number 1 Clutch and the Number 3 Clutch Engaged.

(1) Coupling gear. (2) Number 1 clutch. (3) Number 2 and Number 3 carrier. (7) Number 3 clutch. (8) Number 3 clutch ring gear. (9) Number 3 sun gear. (16) Number 1 carrier. (17) Number 1 sun gear. (18) Input shaft. (19) Number 1 planetary gears. (20) Number 1 clutch ring gear. (22) Number 3 planetary gears. (24) Output shaft.

When the transmission is in third speed reverse, Number 3 clutch (7) and Number 1 clutch (2) are engaged. The Number 1 clutch holds coupling gear (1) stationary. The Number 3 clutch holds ring gear (8) stationary. Input shaft (18) turns Number 1 sun gear (17). Number 1 sun gear turns Number 1 planetary gears (19). Number 1 carrier (16) is a direct mechanical connection with coupling gear (1) .

Because coupling gear (1) is held stationary by the Number 1 clutch, Number 1 carrier (16) is also held stationary. The movement of Number 1 planetary gear (19) causes ring gear (20) to turn in the opposite direction as input shaft (18). Ring gear (20) is a direct mechanical connection with Number 2 carrier (3) and Number 3 carrier (3) .

The movement of Number 2 carrier (3) and Number 3 carrier (3) causes Number 3 planetary gears (22) to move around the inside of the ring gear. This occurs because ring gear (8) is held stationary by the Number 3 clutch. The movement of planetary gears (22) causes Number 3 sun gear (9) to turn. The Number 3 sun gear turns output shaft (24). From the output shaft, power travels through the output transfer gears to the differentials.

Second Speed Reverse

Refer to illustration 1 for the location of the components, as described below. Refer to illustration 4 for a typical description of power flow in the reverse direction.

When the transmission is in second speed reverse, Number 4 clutch (10) and Number 1 clutch (2) are engaged. The Number 1 clutch holds coupling gear (1) stationary. The Number 4 clutch holds ring gear (11) for the Number 4 clutch stationary. Input shaft (18) turns Number 1 sun gear (17). The Number 1 sun gear turns Number 1 planetary gears (19). Number 1 carrier (16) is a direct mechanical connection with coupling gear (1) .

Because coupling gear (1) is held stationary by the Number 1 clutch, Number 1 carrier (16) is also held stationary. The movement of Number 1 planetary gears (19) causes ring gear (20) to turn in the opposite direction as input shaft (18). Ring gear (20) is a direct mechanical connection with Number 2 carrier (3) and Number 3 carrier (3). As the Number 2 carrier and the Number 3 carrier turn, Number 3 planetary gears (22) turn. The Number 3 planetary gears turn ring gear (8) for the Number 3 clutch and Number 3 sun gear (9). Number 3 sun gear (9) turns output shaft (24). Ring gear (8) turns Number 4 carrier (15) .

Because ring gear (11) is held stationary by the Number 4 clutch, planetary gears (23) move around the inside of the ring gear. The movement of planetary gears (23) causes Number 4 sun gear (12) to turn. The Number 4 sun gear turns output shaft (24) .

As a result, the torque to output shaft (24) is divided through Number 3 sun gear (9) and Number 4 sun gear (12). From the output shaft, power travels through the output transfer gears to the differentials.

First Speed Reverse

Refer to illustration 1 for the location of the components, as described below. Refer to illustration 4 for a typical description of power flow in the reverse direction.

When the transmission is in first speed reverse, Number 5 clutch (13) and Number 1 clutch (2) are engaged. The Number 1 clutch holds coupling gear (1) stationary. The Number 5 clutch connects rotating hub (14) and Number 4 carrier (15) .

Input shaft (18) turns Number 1 sun gear (17). The Number 1 sun gear turns planetary gears (19). Number 1 carrier (16) is a direct mechanical connection with coupling gear (1). Because coupling gear (1) is held stationary by the Number 1 clutch, Number 1 carrier (16) is also held stationary. The movement of Number 1 planetary gears (19) causes ring gear (20) to turn in the opposite direction as input shaft (18). Ring gear (20) is a direct mechanical connection with Number 2 carrier (3) and Number 3 carrier (3) .

As carrier (3) turns, planetary gears (22) turn ring gear (8) and sun gear (9). Sun gear (9) turns output shaft (24) .

Ring gear (8) turns carrier (15). Carrier (15) is connected to rotating hub (14) by the engagement of the Number 5 clutch. This allows power to travel from carrier (15) to sun gear (12) and to ring gear (11). The power then travels through the Number 5 clutch to rotating hub (14). Sun gear (12) and rotating hub (14) are fastened to output shaft (24) .

As a result, the torque to output shaft (24) is divided between Number 3 sun gear (9), Number 4 sun gear (12), and rotating hub (14). From the output shaft, power travels through the output transfer gears to the differentials.

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