515 Wheel Skidder and 525 Wheel Skidder Power Train Caterpillar


Transmission

Usage:

525 1DN



Illustration 1g00505087

Transmission Components

(1) Gear

(2) Hub assembly

(3) Input shaft assembly

(4) No. 1 clutch (Low Forward)

(5) Gear (part of shaft assembly (9) )

(6) No. 2 clutch (High Forward)

(7) Gear

(8) Gear assembly

(9) Shaft assembly

(10) Gear (part of shaft assembly (18) )

(11) Gear

(12) Hub assembly

(13) Gear

(14) Gear

(15) Gear

(16) No. 4 clutch (Second Speed)

(17) Gear (part of shaft assembly (26) )

(18) Shaft assembly

(19) Gear

(20) Hub assembly

(21) Gear

(22) No. 3 clutch (Reverse)

(23) Hub assembly

(24) Gear

(25) Hub assembly

(26) Shaft assembly

(27) No. 6 clutch (First Speed)

(28) Gear

(29) No. 5 clutch (Third Speed)

(30) Wave spring

(31) Balance seal assembly

(32) Output shaft assembly

(33) Parking brake assembly

The transmission is a constant mesh type power shift transmission that has five forward speeds and three reverse speeds. The transmission has six clutches that are hydraulically engaged. Five of the clutches are disengaged by a wave spring. First speed clutch (27) is disengaged by wave spring (30) and by balance seal assembly (31). Balance seal assembly (31) fully disengages first speed clutch (27). The balance seal assembly prevents the clutch from not fully disengaging during an overspeed condition. An example of an overspeed condition is coasting down a hill.

Balance seal assembly (31) and wave spring (30) are assembled inside the clutch piston. When the first speed clutch is not engaged, the force from wave spring (30) combines with the lubricating oil pressure between the clutch piston and balance seal assembly (31). The combined force moves the clutch piston into the clutch disengaged position and the combined force holds the clutch piston in this position.




Illustration 2g00505254

Location of the Transmission Shafts

(3) Input shaft assembly. (9) Shaft assembly (Low Forward clutch and High Forward clutch). (18) Shaft assembly (Reverse clutch and Second Speed clutch). (26) Shaft assembly (Third Speed clutch and First Speed clutch). (32) Output shaft assembly.

The transmission contains five shafts: input shaft assembly (3), output shaft assembly (32) and the three main gear shafts. Input shaft assembly (3) is driven by the torque converter turbine. Shaft assembly (9) contains No. 1 clutch (4) and No. 2 clutch (6). Shaft assembly (18) contains No. 3 clutch (22) and No. 4 clutch (16). Shaft assembly (26) contains No. 5 clutch (29) and No. 6 clutch (27) .

Each of the three transmission clutch shafts have three internal oil passages. One passage is for carrying the oil for the lubrication of the clutches, the bearings, and the gears. The clutches, the bearings, and the gears are also cooled by this oil. The other two passages are for carrying pressure oil for the engagement of the clutches on each shaft.

Both a speed clutch and a direction clutch must be engaged in order to send power through the transmission. The speed of the machine and the direction of the machine must be selected manually by the operator.

Table 1
Speed Range and Direction of the Machine     Energized Solenoids     Engaged Clutches    
First Speed Forward     3 and 4     1 and 6    
Second Speed Forward     1 and 4     2 and 6    
Third Speed Forward     3 and 5     1 and 4    
Fourth Speed Forward     1 and 5     2 and 4    
Fifth Speed Forward     1 and 6     2 and 5    
Neutral     -     -    
First Speed Reverse     2 and 4     3 and 6    
Second Speed Reverse     2 and 5     3 and 4    
Third Speed Reverse     2 and 6     3 and 5    

The previous table provides the combination of the solenoids which are energized. The table also provides the clutches that are engaged for each FORWARD speed and for each REVERSE speed.

Parking brake assembly (33) is mounted to the transmission case. Refer to the following service manual modules for additional information about the parking brake: Specifications, SENR6690, "515 & 525 Wheel Skidder Brake System" and Systems Operation/Testing and Adjusting, SENR6691, "515 & 525 Wheel Skidder Brake System".

First Speed Forward




Illustration 3g00505260

Power Flow in First Speed Forward

(1) Gear

(2) Hub assembly

(3) Input shaft assembly

(4) No. 1 clutch (Low Forward)

(5) Gear (part of shaft assembly (9) )

(9) Shaft assembly

(10) Gear (part of shaft assembly (18) )

(13) Gear

(14) Gear

(18) Shaft assembly

(19) Gear

(21) Gear

(23) Hub assembly

(26) Shaft assembly

(27) No. 6 clutch (First Speed)

(28) Gear

(32) Output shaft assembly

When the transmission is in first speed forward, No. 1 clutch (4) and No. 6 clutch (27) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (1) is splined to input shaft assembly (3). Gear (1) is meshed with gear (13). Gear (1) turns gear (13) .

Gear (13) is splined to hub assembly (2) and the gear turns the hub assembly. Torque is transferred from input shaft assembly (3) through gear (1). The torque is then transferred through gear (13) to hub assembly (2). When No. 1 clutch (4) is engaged, torque is transferred from hub assembly (2) through the engaged No. 1 clutch to shaft assembly (9) .

Gear (5) is part of shaft assembly (9). Gear (5) is meshed with gear (10). Gear (10) is turned by gear (5). Gear (10) is a part of shaft assembly (18). Torque is transferred from shaft assembly (9) through gear (5). The torque is then transferred through gear (10) to shaft assembly (18) .

Gear (14) is splined to shaft assembly (18). Gear (14) is meshed with gear (19). Gear (19) is turned by gear (14). Gear (19) is splined to hub assembly (23). Torque is transferred from shaft assembly (18) through gear (14). The torque is then transferred through gear (19) to hub assembly (23). When No. 6 clutch (27) is engaged, torque is transferred from hub assembly (23) through the engaged No. 6 clutch to shaft assembly (26) .

Gear (21) is splined to shaft assembly (26). Gear (21) is meshed with gear (28). Gear (28) is turned by gear (21). Gear (28) is splined to output shaft assembly (32). Torque is transferred from shaft assembly (26) through gear (21) and through gear (28) to output shaft assembly (32) .

Second Speed Forward




Illustration 4g00505357

Power Flow in Second Speed Forward

(3) Input shaft assembly

(5) Gear (part of shaft assembly (9) )

(6) No. 2 clutch (High Forward)

(7) Gear

(8) Gear assembly

(9) Shaft assembly

(10) Gear (part of shaft assembly (18) )

(14) Gear

(18) Shaft assembly

(19) Gear

(21) Gear

(23) Hub assembly

(26) Shaft assembly

(27) No. 6 clutch (Low Speed)

(28) Gear

(32) Output shaft assembly

When the transmission is in second speed forward, No. 2 clutch (6) and No. 6 clutch (27) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (7) is splined to input shaft assembly (3). Gear (7) is meshed with gear assembly (8). Gear assembly (8) is turned by gear (7) .

Gear assembly (8) is splined to shaft assembly (9). Torque is transferred from input shaft assembly (3) through gear (7) and through gear assembly (8) to shaft assembly (9). When No. 2 clutch (6) is engaged, torque is transferred from gear assembly (8) through the engaged No. 2 clutch (6) to shaft assembly (9) .

Gear (5) is part of shaft assembly (9). Gear (5) is meshed with gear (10). Gear (10) is turned by gear (5). Gear (10) is part of shaft assembly (18). Torque is transferred from shaft assembly (9) through gear (5) and through gear (10) to shaft assembly (18) .

Gear (14) is part of shaft assembly (18). Gear (14) is meshed with gear (19). Gear (19) is turned by gear (14). Gear (19) is part of shaft assembly (26). Torque is transferred from shaft assembly (18) through gear (14) and through gear (19) to shaft assembly (26). When No. 6 clutch (27) is engaged, torque is transferred from hub assembly (23) through the engaged No. 6 clutch to shaft assembly (26) .

Gear (21) is splined to shaft assembly (26). Gear (21) is meshed with gear (28). Gear (28) is turned by gear (21). Gear (28) is splined to output shaft assembly (32). Torque is transferred from shaft assembly (26) through gear (21) and through gear (28) to output shaft assembly (32) .

Third Speed Forward




Illustration 5g00510670

Power Flow in Third Speed Forward

(1) Gear

(2) Hub assembly

(3) Input shaft assembly

(4) No. 1 clutch (Low Forward)

(5) Gear (part of shaft assembly (9) )

(9) Shaft assembly

(10) Gear (part of shaft assembly (18) )

(11) Gear

(12) Hub assembly

(13) Gear

(16) No. 4 clutch (Second Speed)

(17) Gear

(18) Shaft assembly

(21) Gear

(26) Shaft assembly

(28) Gear

(32) Output shaft assembly

When the transmission is in third speed forward, No. 1 clutch (4) and No. 4 clutch (16) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (1) is splined to input shaft assembly (3). Gear (1) is meshed with gear (13). Gear (13) is turned by gear (1) .

Gear (13) is splined to hub assembly (2). Hub assembly (2) is turned by gear (13). Torque is transferred from input shaft assembly (3) through gear (1) and through gear (13) to hub assembly (2). When No. 1 clutch (4) is engaged, torque is transferred from hub assembly (2) through the engaged No. 1 clutch to shaft assembly (9) .

Gear (5) is part of shaft assembly (9). Gear (5) is meshed with gear (10). Gear (10) is turned by gear (5). Gear (10) is part of shaft assembly (18). Torque is transferred from shaft assembly (9) through gear (5) and through gear (10) to shaft assembly (18) .

When No. 4 clutch (16) is engaged, torque is transferred from shaft assembly (18) through the engaged No. 4 clutch to hub assembly (12). Gear (11) is splined to hub assembly (12). Gear (11) is meshed with gear (17). Gear (17) is turned by gear (11). Gear (17) is part of shaft assembly (26). Torque is transferred from hub assembly (12) through gear (11) and through gear (17) to shaft assembly (26) .

Gear (21) is splined to shaft assembly (26). Gear (21) is meshed with gear (28). Gear (28) is turned by gear (21). Gear (28) is splined to output shaft assembly (32). Torque is transferred from shaft assembly (26) through gear (21) and through gear (28) to output shaft assembly (32) .

Fourth Speed Forward




Illustration 6g00505477

Power Flow in Fourth Speed Forward

(3) Input shaft assembly

(5) Gear (part of shaft assembly (9) )

(6) No. 2 clutch (High Forward)

(7) Gear

(8) Gear assembly

(9) Shaft assembly

(10) Gear (part of shaft assembly (18) )

(11) Gear

(12) Hub assembly

(16) No. 4 clutch (Second Speed)

(17) Gear (part of shaft assembly (26) )

(18) Shaft assembly

(21) Gear

(26) Shaft assembly

(28) Gear

(32) Output shaft assembly

When the transmission is in fourth speed forward, No. 2 clutch (6) and No. 4 clutch (16) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (7) is splined to input shaft assembly (3). Gear (7) is meshed with gear assembly (8). Gear assembly (8) is turned by gear (7) .

Gear assembly (8) is splined to shaft assembly (9). Gear assembly (8) is turned by gear (7). Torque is transferred from input shaft assembly (3) through gear (7) and through gear assembly (8). When No. 2 clutch (6) is engaged, torque is transferred from gear assembly (8) through the engaged No. 2 clutch to shaft assembly (9) .

Gear (5) is part of shaft assembly (9). Gear (5) is meshed with gear (10). Gear (10) is turned by gear (5). Gear (10) is part of shaft assembly (18). Torque is transferred from shaft assembly (9) through gear (5) and through gear (10) to shaft assembly (18) .

When No. 4 clutch (16) is engaged, torque is transferred from shaft assembly (18) through the engaged No. 4 clutch to hub assembly (12). Gear (11) is splined to hub assembly (12). Gear (11) is meshed with gear (17). Gear (17) is turned by gear (11). Gear (17) is part of shaft assembly (26). Torque is transferred from hub assembly (12) through gear (11) and through gear (17) to shaft assembly (26) .

Gear (21) is splined to shaft assembly (26). Gear (21) is meshed with gear (28). Gear (28) is turned by gear (21). Gear (28) is splined to output shaft assembly (32). Torque is transferred from shaft assembly (26) through gear (21). The torque is then transferred through gear (28) to output shaft assembly (32) .

Fifth Speed Forward




Illustration 7g00505512

Power Flow in Fifth Speed Forward

(3) Input shaft assembly

(5) Gear (part of shaft assembly (9) )

(6) No. 2 clutch (High Forward)

(7) Gear

(8) Gear assembly

(9) Shaft assembly

(10) Gear (part of shaft assembly (18) )

(18) Shaft assembly

(21) Gear

(24) Gear

(25) Hub assembly

(26) Shaft assembly

(28) Gear

(29) No. 5 clutch (Third Speed)

(32) Output shaft assembly

When the transmission is in fifth speed forward, No. 2 clutch (6) and No. 5 clutch (29) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (7) is splined to input shaft assembly (3). Gear (7) is meshed with gear assembly (8). Gear assembly (8) is turned by gear (7) .

Gear assembly (8) is splined to shaft assembly (9). Gear assembly (8) is turned by gear (7). Torque is transferred from input shaft assembly (3) through gear (7). The torque is then transferred through gear assembly (8) to shaft assembly (9). When No. 2 clutch (6) is engaged, torque is transferred from gear assembly (8) through the engaged No. 2 clutch to shaft assembly (9) .

Gear (5) is part of shaft assembly (9). Gear (5) is meshed with gear (10). Gear (10) is turned by gear (5). Gear (10) is part of shaft assembly (18). Gear (10) is meshed with gear (24). Gear (24) is turned by gear (10). Gear (24) is splined to hub assembly (25). Torque is transferred from shaft assembly (9) through gear (5). The torque is transferred from gear (5) to gear (10). The torque is then transferred through gear (10) to gear (24) .

When No. 5 clutch (29) is engaged, torque is transferred from hub assembly (25) through the engaged No. 5 clutch to shaft assembly (26).

Gear (21) is splined to shaft assembly (26). Gear (21) is meshed with gear (28). Gear (28) is turned by gear (21). Gear (28) is splined to output shaft assembly (32). Torque is transferred from shaft assembly (26) through gear (21). The torque is then transferred through gear (28) to output shaft assembly (32) .

Neutral

When the transmission is in neutral, no clutches are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Because No. 1 clutch (4), No. 2 clutch (6), or No. 3 clutch (22) are not engaged, there is no torque transfer from input shaft assembly (3) to either shaft assembly (9) or shaft assembly (18) .

First Speed Reverse




Illustration 8g00510340

Power Flow in First Speed Reverse

(1) Gear

(3) Input shaft assembly.

(14) Gear

(15) Gear (part of shaft assembly (18) )

(18) Shaft assembly

(19) Gear

(20) Hub assembly

(21) Gear

(22) No. 3 clutch (Reverse)

(23) Hub assembly

(26) Shaft assembly

(27) No. 6 (First Speed)

(28) Gear

(32) Output shaft assembly

When the transmission is in first speed reverse, No. 3 clutch (22) and No. 6 clutch (27) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (1) is splined to input shaft assembly (3). Gear (1) is meshed with gear (15). Gear (15) is turned by gear (1) .

Gear (15) is splined to hub assembly (20). Hub assembly (20) is turned by gear (15). Torque is transferred from input shaft assembly (3) through gear (1). The torque is then transferred through gear (15) to hub assembly (20). When No. 3 clutch (22) is engaged, torque is transferred from hub assembly (20) through the engaged No. 3 clutch to shaft assembly (18) .

Gear (15) is splined to shaft assembly (18). Gear (14) is meshed with gear (19). Gear (19) is turned by gear (14). Gear (19) is splined to hub assembly (23). Torque is transferred from shaft assembly (18) through gear (14). The torque is then transferred through gear (19) to hub assembly (23). When the No. 6 clutch (27) is engaged, torque is transferred from hub assembly (23) through the engaged No. 6 clutch (27) to shaft assembly (26) .

Gear (21) is splined to shaft assembly (26). Gear (21) is meshed with gear (28). Gear (28) is turned by gear (21). Gear (28) is splined to output shaft assembly (32). Torque is transferred from shaft assembly (26) through gear (21). The torque is then transferred through gear (28) to output shaft assembly (32) .

Second Speed Reverse




Illustration 9g00505595

Power Flow in Second Speed Reverse

(1) Gear

(3) Input shaft assembly.

(11) Gear

(12) Hub assembly

(15) Gear

(16) No. 4 clutch (Second Speed)

(17) Gear (part of shaft assembly (26) )

(18) Shaft assembly

(20) Hub assembly

(21) Gear

(22) No. 3 clutch (Reverse)

(26) Shaft assembly

(28) Gear

(32) Output shaft assembly

When the transmission is in second speed reverse, No. 3 clutch (22) and No. 4 clutch (16) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (1) is splined to input shaft assembly (3). Gear (1) is meshed with gear (15). Gear (15) is turned by gear (1) .

Gear (15) is splined to hub assembly (20). Hub assembly (20) is turned by gear (15). Torque is transferred from input shaft assembly (3) through gear (1). The torque is transferred from gear (1) through gear (15). The torque is then transferred to hub assembly (20). When No. 3 clutch (22) is engaged, torque is transferred from hub assembly (20) through the engaged No. 3 clutch to shaft assembly (18) .

When No. 4 clutch (16) is engaged, torque is transferred from shaft assembly (18) through the engaged No. 4 clutch to hub assembly (12). Gear (11) is splined to hub assembly (12). Gear (11) is meshed with gear (17). Gear (17) is turned by gear (11). Gear (17) is part of the shaft assembly (26). Torque is transferred from hub assembly (12) through gear (11). The torque is then transferred through gear (17) to shaft assembly (26) .

Gear (21) is splined to shaft assembly (26). Gear (21) is meshed with gear (28). Gear (28) is turned by gear (21). Gear (28) is splined to output shaft assembly (32). Torque is transferred from shaft assembly (26) through gear (21). The torque is then transferred through gear (28) to output shaft assembly (32) .

Third Speed Reverse




Illustration 10g00505646

Power Flow in Third Speed Reverse

(1) Gear

(3) Input shaft assembly.

(10) Gear (part of shaft assembly (18) )

(15) Gear

(18) Shaft assembly

(20) Hub assembly

(21) Gear

(22) No. 3 clutch (Reverse)

(24) Gear

(25) Hub assembly

(26) Shaft assembly

(28) Gear

(29) No. 5 clutch (Third Speed)

(32) Output shaft assembly

When the transmission is in third speed reverse, No. 3 clutch (22) and No. 5 clutch (29) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (1) is splined to input shaft assembly (3). Gear (1) is meshed with gear (15). Gear (15) is turned by gear (1) .

Gear (15) is splined to hub assembly (20). Hub assembly (20) is turned by gear (15). Torque is transferred from input shaft assembly (3) through gear (1). The torque is then transferred through gear (15) to hub assembly (20). When No. 3 clutch (22) is engaged, torque is transferred from hub assembly (20) through the engaged No. 3 clutch to shaft assembly (18) .

Gear (10) is part of shaft assembly (18). Gear (10) is meshed with gear (24). Gear (24) is turned by gear (10). Gear (24) is splined to hub assembly (25). Torque is transferred from shaft assembly (18) through gear (10). The torque is transferred from gear (10) to gear (24). The torque is then transferred through gear (24) to hub assembly (25) .

When No. 5 clutch (29) is engaged, torque is transferred from hub assembly (25) through the engaged No. 5 clutch to shaft assembly (26).

Gear (21) is splined to shaft assembly (26). Gear (21) is meshed with gear (28). Gear (28) is turned by gear (21). Gear (28) is splined to output shaft assembly (32). Torque is transferred from shaft assembly (26) through gear (21). The torque is then transferred through gear (28) to output shaft assembly (32) .

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