This section highlights the specific location of the components that will be covered in this part of the manual.
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| Illustration 1 | g03422101 |
| (1) Transmission control valve | |
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| Illustration 2 | g03422107 |
| (2) Transmission planetary | |
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| Illustration 3 | g03422163 |
| (3) Transmission speed sensors | |
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| Illustration 4 | g03423949 |
| (4) Engine speed sensor | |
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| Illustration 5 | g03424091 |
| (5) Intermediate speed sensor | |
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| Illustration 6 | g03424097 |
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Top view of the transmission control valve (6) Torque converter speed sensor | |
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| Illustration 7 | g03424099 |
| (7) Torque converter oil temperature sensor | |
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| Illustration 8 | g03424100 |
| (8) Transmission oil temperature sensor | |
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| Illustration 9 | g03424104 |
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Side view of the tractor wheel assembly (9) Wheel speed sensors (left and right) | |
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| Illustration 10 | g03424107 |
| (10) Transmission shift lever | |
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| Illustration 11 | g03427934 |
| (11) Engine retarder control | |
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| Illustration 12 | g03427953 |
| (12) Compression brake solenoids | |
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| Illustration 13 | g03632899 |
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Transmission hydraulic schematic (1) Clutch modulating valve and clutch (2) Clutch modulating valve and clutch (3) Clutch modulating valve and clutch (4) Clutch modulating valve and clutch (5) Clutch modulating valve and clutch (6) Clutch modulating valve and clutch (7) Clutch modulating valve and clutch (8) Main relief valve (9) Transmission control arrangement (10) Torque converter inlet relief valve (11) Torque converter (12) Filter screen (13) Scavenge pump (14) Lube circuit for clutches (1) and (2) ( 15) Lube circuit for clutches (3) through (7) ( 16) Transmission filter (17) Transmission pump (18) Filter screen (19) Transmission sump (20) Case sump (21) Pump housing (22) Suction screen (23) Brake cooling pump (24) ECM J1 connector (25) ECM J2 connector (26) Torque converter temperature sensor (27) Transmission temperature sensor (A) Transmission oil cooler and flywheel sump (B) Brake cooling circuit | |
Oil starts at case sump (20). The oil is drawn up through filter screen (18) by transmission pump (17). The oil is pushed through transmission filter (16) before the oil reaches transmission control arrangement (9). Once the oil is inside transmission control arrangement (9), the oil is diverted to clutch modulating valves (1) through (7) through main relief valve (8). The oil is fed to each clutch modulating valve by a common oil galley.
When the clutch modulating valve is not engaged, oil flow is directed through the valve spool and back to transmission sump (19). When a shift takes place, the transmission electronic control unit (ECM) (24) and (25) modulates the solenoid on the clutch modulation valve. This action shifts the control spool in each valve to redirect oil flow to the corresponding clutch. When the modulation valve shifts back to the rest position, oil is allowed to flow back to transmission sump (19). From here, the oil is picked up and sent through the filter screen (12) before being pushed through scavenge pump (13). The oil is then sent to case sump (20).
Lubrication and Torque Converter
Oil starts at case sump (20). The oil is drawn up through filter screen (18) by transmission pump (17). The oil is pushed through transmission filter (16) before the oil reaches transmission control arrangement (9). Once the oil is inside transmission control arrangement (9), the oil is diverted to lubrication circuits (14) and (15) and torque converter (11) through main relief valve (8) and lubrication circuit relief valve (10). Lubrication for clutches one and two (14) gets some of the oil flow which is then returned to transmission sump (19). The remainder of the oil flow supplies oil to torque converter (11). After the oil passes through the torque converter, the oil is then sent to transmission oil cooler (A) and the lubrication circuit for clutches three through seven (15), before the oil is returned to the flywheel sump. The oil then drains to transmission sump (19). From here, the oil is picked up and sent through filter screen (12) before being pushed through scavenge pump (13). The oil is then sent to case sump (20).
The torque converter oil temperature sensor (26) is a passive analog sensor that is located at the torque converter output. The sensor is used to drive the torque converter temperature gauge on the instrument cluster. If the ECM determines that the resistance of this sensor is too high or too low, the ECM logs a diagnostic code for the sensor.
The transmission oil temperature sensor (27) allows the Transmission/Chassis ECM to monitor the temperature of the transmission oil. The sensor provides a passive analog (resistance) input signal to the ECM.
The ECM associates the resistance value of the sensor signal with a specific temperature of the transmission oil.
The resistance range of the sensor that the ECM will consider valid is 33650 ohms at
If the ECM detects that the resistance of the sensor circuit is 52.6 ohms, the resistance is equal to
A resistance of the sensor circuit greater than 33650 ohms or less than 18.6 ohms activates a diagnostic code.
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| Illustration 14 | g02556477 |
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Transmission Components (1) Planetary gears (2) Ring gear (3) No. 1 clutch (4) Planetary carrier (5) Hub gear (6) Planetary gears (7) No. 2 clutch (8) Planetary carrier (9) Ring gear (10) No. 3 clutch (11) Center shaft (12) Hub gear (13) No. 4 clutch (14) Planetary carrier and clutch housing (15) Ring gear (16) No. 5 clutch (17) Planetary gears (18) Ring gear (19) No. 6 clutch (20) Planetary gears (21) Sun gear (22) No. 7 clutch (23) Ring gear (24) Planetary gears (25) Sun gear (26) Planetary carrier and output hub (27) Planetary gears (28) Sun gear (29) Input hub (converter drive) (30) Input shaft (direct drive) | |
Power from the engine is transferred through the drive shaft to the transfer gears. The transfer gears drive the torque converter which delivers power to the transmission. The transmission delivers power to the differential and the final drives.
The transmission has a combination of five stationary clutches, three planetary units, and two rotating clutches. The No. 2 clutch (7) and No. 4 clutch (13) are the rotating clutches. The components consist of eight speeds FORWARD and one speed REVERSE. REVERSE, FIRST, and SECOND speeds are torque converter drive. THIRDthroughEIGHTH speeds are direct drive. Transmission clutches are numbered from the input to the output end.
Power input and output are on opposite ends of the transmission. Input power is sent from the torque converter. The torque converter drives the transmission input. Center shaft (11) carries the sun gears that drive the output section. Center shaft (11) turns the same direction as input hub (29) and input shaft (30).
The input section of the transmission contains the No. 1 clutch (3), No. 2 clutch (7) and No. 3 clutch (10). The No. 1 clutch is engaged in torque converter drive. The No. 2 clutch or the No. 3 clutch is engaged in direct drive. Planetary carrier (4), planetary carrier (8) and center shaft (11) are fastened together. Planetary carrier (4), planetary carrier (8) and center shaft (11) turn as one unit.
Power from the converter drives input hub (29). Sun gear (28) is assembled to the input hub. Sun gear (28) rotates with input hub (29). Power is sent to No. 1 clutch (3).
Power from the direct drive rotates input shaft (30). Power is sent to No. 2 clutch (7) or No. 3 clutch (10).
The output section of the transmission contains the No. 4 clutch (13), No. 5 clutch (16), No. 6 clutch (19) and No. 7 clutch (22). The No. 7 clutch provides REVERSE speed. The No. 7 clutch has two sets of planetary gears. The planetary carrier and clutch housing (14) is fastened to ring gear (18). The planetary carrier and clutch housing (14) turn as one unit with ring gear (18).
| Transmission Speed | Engaged Clutches |
| REVERSE | 1 and 7 |
| NEUTRAL | 4 |
| FIRST Speed | 1 and 6 |
| SECOND Speed | 1 and 5 |
| THIRD Speed | 3 and 6 |
| FOURTH Speed | 2 and 6 |
| FIFTH Speed | 3 and 5 |
| SIXTH Speed | 2 and 5 |
| SEVENTH Speed | 3 and 4 |
| EIGHTH Speed | 2 and 4 |
Transmission in NEUTRAL
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| Illustration 15 | g02556677 |
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Transmission in NEUTRAL (1) Planetary gears (2) Ring gear (3) No. 1 clutch (4) Planetary carrier (5) Hub gear (6) Planetary gears (7) No. 2 clutch (8) Planetary carrier (9) Ring gear (10) No. 3 clutch (11) Center shaft (12) Hub gear (13) No. 4 clutch (14) Planetary carrier and clutch housing (15) Ring gear (16) No. 5 clutch (17) Planetary gears (18) Ring gear (19) No. 6 clutch (20) Planetary gears (21) Sun gear (22) No. 7 clutch (23) Ring gear (24) Planetary gears (25) Sun gear (26) Planetary carrier and output hub (27) Planetary gears (28) Sun gear (29) Input hub (converter drive) (30) Input shaft (direct drive) | |
Only the No. 4 clutch (13) is engaged in NEUTRAL. The No. 1 clutch (3), No. 2 clutch (7) and the No. 3 clutch (10) (all input clutches) are not engaged. Power is delivered from the transfer gears to both input hub (29) and input shaft (30).
Sun gear (28) is splined to input hub (29) and turns with input hub (29). Sun gear (28) spins planetary gears (1) which spin ring gear (2). Ring gear (2) spins the clutch discs in No. 1 clutch (3). There is no held member. Some of the power is lost in the clutch discs that are spinning.
Hub gear (5) is splined to input shaft (30) and turns with input shaft (30). Hub gear (5) spins the clutch discs in No. 2 clutch (7). There is no held member. Some of the power is lost in the clutch discs that are spinning.
Hub gear (5) also spins planetary gears (6). Planetary gears (6) spin ring gear (9) which now spins the discs in No. 3 clutch (10). There is no held member. The remainder of the input power is lost in the clutch discs that are spinning. No power is transferred to the output section of the transmission.
No. 4 clutch (13) is engaged and No. 4 clutch (13) holds hub gear (12). Hub gear (12) is splined to center shaft (11) and hub gear (12) holds center shaft (11). Planetary carrier (4) and planetary carrier (8) are bolted together. Planetary carrier (8) is splined to center shaft (11). Center shaft (11) holds both carriers. With no input power to center shaft (11), no output power is generated.
Transmission in FIRST Speed
No. 1 clutch (3) and No. 6 clutch (19) are engaged in FIRST speed. The output power of the converter drives input hub (29). Sun gear (28) is splined to input hub (29) and turns with input hub (29). Sun gear (28) spins planetary gears (1). Planetary gears (1) attempt to spin ring gear (2). The No. 1 clutch is engaged and the No. 1 clutch holds ring gear (2). Since ring gear (2) is being held, planetary gears (1) rotate around the inside of ring gear (2). This drives planetary carrier (4) in the same direction as input hub (29). Planetary carrier (4) is bolted to planetary carrier (8). Planetary carrier (4) turns planetary carrier (8). Planetary carrier (8) is splined to center shaft (11). Center shaft (11) now turns in the same direction as input hub (29).
Sun gear (21) is splined to center shaft (11) and turns with center shaft (11). Sun gear (21) spins planetary gears (20). Planetary gears (20) attempt to spin ring gear (18). No. 6 clutch (19) is engaged. The No. 6 clutch holds ring gear (18). Since ring gear (18) is being held, planetary gears (20) rotate around the inside of ring gear (18). This actiondrives the planetary carrier and output hub (26) in the same direction as input hub (29).
Transmission in SECOND Speed
No. 1 clutch (3) and No. 5 clutch (16) are engaged in SECOND speed. The output power of the converter drives input hub (29). Sun gear (28) is splined to input hub (29) and turns with input hub (29). Sun gear (28) spins planetary gears (1). Planetary gears (1) attempt to spin ring gear (2). The No. 1 clutch is engaged. The No. 1 clutch holds ring gear (2). Since ring gear (2) is being held, planetary gears (1) rotate around the inside of ring gear (2). This drives planetary carrier (4) in the same direction as input hub (29). Planetary carrier (4) is bolted to planetary carrier (8). Planetary carrier (4) turns planetary carrier (8). Planetary carrier (8) is splined to center shaft (11). Center shaft (11) now turns in the same direction as input hub (29).
Hub gear (12) is splined to center shaft (11) and turns with center shaft (11). Hub gear (12) spins planetary gears (17). Planetary gears (17) attempt to spin ring gear (15). No. 5 clutch (16) is engaged. No. 5 clutch (16) holds ring gear (15). Since ring gear (15) is being held, planetary gears (17) rotate around the inside of ring gear (15). This rotation drives the planetary carrier and clutch housing (14) in the same direction as center shaft (11). Ring gear (18) is splined to the planetary carrier and clutch housing (14). The planetary carrier and clutch housing (14) turn as one unit with ring gear (18).
Sun gear (21) is splined to the center shaft (11) and turns with center shaft (11). When sun gear (21) and ring gear (18) turn in the same direction but at different speeds, this rotation drives planetary gears (20). As planetary gears (20) move, the planetary carrier and output hub (26) is also driven. The planetary carrier and output hub (26) will turn in the same direction as input hub (29).
Transmission in THIRD Speed
No. 3 clutch (10) and No. 6 clutch (19) are engaged in THIRD speed. The output power of the torque converter drives input shaft (30). Hub gear (5) is splined to input shaft (30). Hub gear (5) turns with input shaft (30). The No. 3 clutch is engaged. The No. 3 clutch holds ring gear (9). Hub gear (5) spins planetary gears (6). Planetary gears (6) attempt to spin ring gear (9). Since ring gear (9) is being held, planetary gears (6) rotate around the outside of ring gear (9). This drives planetary carrier (8). Planetary carrier (8) is splined to center shaft (11). Center shaft (11) now turns in the same direction as input shaft (30).
Sun gear (21) is splined to center shaft (11) and turns with center shaft (11). Sun gear (21) spins planetary gears (20). Planetary gears (20) attempt to spin ring gear (18). No. 6 clutch (19) is engaged. The No. 6 clutch holds ring gear (18). Since ring gear (18) is being held, planetary gears (20) rotate around the inside of ring gear (18). This drives the planetary carrier and output hub (26) in the same direction as input hub (29).
Transmission in FOURTH Speed
No. 2 clutch (7) and No. 6 clutch (19) are engaged in FOURTH speed. The output power of the torque converter drives input shaft (30). Hub gear (5) is splined to input shaft (30) and turns with input shaft (30). The No. 2 clutch is engaged. The No. 2 clutch holds hub gear (5). Now planetary carrier (8), hub gear (5), and input shaft (30) turn as one unit. Planetary carrier (8) is splined to center shaft (11). Center shaft (11) turns in the same direction as input shaft (30). Power is transferred from input shaft (30) to center shaft (11).
Sun gear (21) is splined to center shaft (11) and turns with center shaft (11). Sun gear (21) spins planetary gear (20). Planetary gears (20) attempt to spin ring gear (18). No. 6 clutch (19) is engaged. The No. 6 clutch holds ring gear (18). Since ring gear (18) is being held, planetary gears (20) rotate around the inside of ring gear (18). This drives the planetary carrier and output hub (26) in the same direction as input hub (29).
Transmission in FIFTH Speed
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| Illustration 16 | g02557876 |
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Transmission in FIFTH Speed (1) Planetary gears (2) Ring gear (3) No. 1 clutch (4) Planetary carrier (5) Hub gear (6) Planetary gears (7) No. 2 clutch (8) Planetary carrier (9) Ring gear (10) No. 3 clutch (11) Center shaft (12) Hub gear (13) No. 4 clutch (14) Planetary carrier and clutch housing (15) Ring gear (16) No. 5 clutch (17) Planetary gears (18) Ring gear (19) No. 6 clutch (20) Planetary gears (21) Sun gear (22) No. 7 clutch (23) Ring gear (24) Planetary gears (25) Sun gear (26) Planetary carrier and output hub (27) Planetary gears (28) Sun gear (29) Input hub (converter drive) (30) Input shaft (direct drive) | |
No. 3 clutch (10) and No. 5 clutch (16) are engaged in FIFTH speed. The output power of the torque converter drives input shaft (30). Hub gear (5) is splined to input shaft (30) and turns with input shaft (30). The No. 3 clutch is engaged. The No. 3 clutch holds ring gear (9). Hub gear (5) spins planetary gears (6). Planetary gears (6) attempt to spin ring gear (9). Since ring gear (9) is being held, planetary gears (6) rotate around the outside of ring gear (9). This drives planetary carrier (8). Planetary carrier (8) is splined to center shaft (11). Center shaft (11) now turns in the same direction as input shaft (30).
Hub gear (12) is splined to center shaft (11) and turns with center shaft (11). Hub gear (12) spins planetary gears (17). Planetary gears (17) attempt to spin ring gear (15).
No. 5 clutch (16) is engaged. The No. 5 clutch holds ring gear (15). Since ring gear (15) is being held, planetary gears (17) rotate around the inside of ring gear (15). This action drives the planetary carrier and clutch housing (14) in the same direction as center shaft (11). Ring gear (18) is assembled to the planetary carrier and clutch housing (14). The planetary carrier and clutch housing (14) turns as one unit with ring gear (18).
Sun gear (21) is splined to center shaft (11) and turns with center shaft (11). While sun gear (21) and ring gear (18) turn in the same direction, but at different speed, planetary gears (20) are driven. As planetary gears (20) move, the planetary carrier and output hub (26) is also driven. The planetary carrier and output hub (26) turns in the same direction as input hub (29).
Transmission in SIXTH Speed
No. 2 clutch (7) and No. 5 clutch (16) are engaged in SIXTH speed. The output power of the torque converter drives input shaft (30). Hub gear (5) is splined to input shaft (30) and turns with input shaft (30). The No. 2 clutch is engaged. The No. 2 clutch holds hub gear (5). Now planetary carrier (8), hub gear (5), and input shaft (30) turn as one unit. Planetary carrier (8) is splined to center shaft (11). Center shaft (11) turns in the same direction as input shaft (30). Power is transferred from input shaft (30) to center shaft (11).
Hub gear (12) is splined to center shaft (11) and turns with center shaft (11). Hub gear (12) spins planetary gears (17). Planetary gears (17) attempt to spin ring gear (15). No. 5 clutch (16) is engaged and No. 5 clutch (16) holds ring gear (15). Since ring gear (15) is being held, planetary gears (17) rotate around the inside of ring gear (15). This action drives the planetary carrier and clutch housing (14) in the same direction as center shaft (11). Ring gear (18) is assembled to the planetary carrier and clutch housing (14). The planetary carrier and clutch housing (14) turns as one unit with ring gear (18).
Sun gear (21) is splined to center shaft (11) and turns with center shaft (11). When sun gear (21) and ring gear (18) turn in the same direction at different speeds, this action will drive planetary gears (20). As planetary gears (20) move, the planetary carrier and output hub (26) is also driven. The planetary carrier and output hub (26) turn in the same direction as input hub (29).
Transmission in SEVENTH Speed
No. 3 clutch (10) and No. 4 clutch (13) are engaged in SEVENTH speed. The output power of the torque converter drives input shaft (30). Hub gear (5) is splined to input shaft (30) and turns with input shaft (30). The No. 3 clutch is engaged. The No. 3 clutch holds ring gear (9). Hub gear (5) spins planetary gears (6). Planetary gears (6) attempt to spin ring gear (9). Since ring gear (9) is being held, planetary gears (6) rotate around the outside of ring gear (9). This drives planetary carrier (8). Planetary carrier (8) is splined to center shaft (11). Center shaft (11) now turns in the same direction as input shaft (30).
Hub gear (12) is splined to center shaft (11). Hub gear (12) turns with center shaft (11). No. 4 clutch (13) is engaged and No. 4 clutch (13) holds hub gear (12). The following components will turn as one unit:
- Center shaft (11)
- Hub gear (12)
- No. 4 clutch (13)
- Planetary carrier and clutch housing (14)
- Ring gear (18)
Sun gear (21) is splined to center shaft (11) and turns with center shaft (11).
When sun gear (21) and ring gear (18) turn in the same direction at the same speed, planetary gears (20) are held. This action drives the planetary carrier and output hub (26) in the same direction and at the same speed as center shaft (11).
Transmission in EIGHTH Speed
No. 2 clutch (7) and No. 4 clutch (13) are engaged in EIGHTH speed. The output power for the torque converter drives input shaft (30). Hub gear (5) is splined to input shaft (30) and turns with input shaft (30). The No. 2 clutch is engaged. The No. 2 clutch holds hub gear (5). Now planetary carrier (8), hub gear (5), and input shaft (30) turn as one unit. Planetary carrier (8) is splined to center shaft (11). Center shaft (11) turns in the same direction as input shaft (30). Power is transferred from input shaft (30) to center shaft (11).
Hub gear (12) is splined to center shaft (11) and turns with center shaft (11). No. 4 clutch (13) is engaged and No. 4 clutch (13) holds hub gear (12). The following components will turn as one unit:
- Center shaft (11)
- Hub gear (12)
- No. 4 clutch (13)
- Planetary carrier and clutch housing (14)
- Ring gear (18)
Sun gear (21) is splined to center shaft (11) and turns with center shaft (11).
When sun gear (21) and ring gear (18) turn in the same direction at the same speed, planetary gears (20) are held. This action drives the planetary carrier and output hub (26) in the same direction and at the same speed as center shaft (11).
Transmission in REVERSE
No. 1 clutch (3) and No. 7 clutch (22) are engaged in REVERSE. The output power for the converter drives input hub (29). Sun gear (28) is assembled to input hub (29) and turns with input hub (29). Sun gear (28) spins planetary gears (1). Planetary gears (1) attempt to spin ring gear (2). The No. 1 clutch (3) is engaged. The No. 1 clutch holds ring gear (2). Since ring gear (2) is being held, planetary gears (1) rotate around the inside of ring gear (2). This drives planetary carrier (4) in the same direction as input hub (29). Planetary carrier (4) is bolted to planetary carrier (8). Planetary carrier (4) turns planetary carrier (8). Planetary carrier (8) is splined to center shaft (11). Center shaft (11) now turns in the same direction as input hub (29).
Sun gear (25) is splined to center shaft (11) and turns with center shaft (11). Sun gear (25) spins planetary gears (27). Planetary gears (27) spin planetary gears (24). Planetary gears (24) attempt to spin ring gear (23). No. 7 clutch (22) is engaged. The No. 7 clutch holds ring gear (23). Since ring gear (23) is being held, planetary gears (24) rotate around the inside of ring gear (23). This drives the planetary carrier and output hub (26) in the opposite direction of input hub (29) and center shaft (11).
Transmission Lubrication
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| Illustration 17 | g02559076 |
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Transmission Lubrication (1) Planetary gears (3) No. 1 clutch (6) Planetary gears (7) No. 2 clutch (10) No. 3 clutch (16) No. 5 clutch (17) Planetary gears (19) No. 6 clutch (20) Planetary gears (22) No. 7 clutch (24) Planetary gears (27) Planetary gears (31) Passage for converter inlet oil (32) Balance piston for No. 2 clutch (33) Bearing (34) Lubrication inlet passage (35) Bearing (36) Bearing (37) Balance piston for No. 4 clutch (38) Passage (39) Bearing | |
Oil for lubrication of the transmission flows from the transmission oil cooler. Also, lubrication oil is provided by the retarder control valve on wheel tractors. In both cases, oil flows downward through the distribution manifold in the bottom of the transmission hydraulic control group.
Lubrication oil to the transmission is supplied through two different passages. Converter inlet oil from passage (31) in the No. 1 clutch housing lubricates bearing (39), No. 1 clutch (3) and planetary gears (1). Oil is also routed to the rearward side of balance piston (32) through passage (38).
The second path for lubrication oil is through passage (34) in the No. 4 clutch housing. This oil divides. Some of the oil flows downward through passage (34) to center shaft (11). This oil flows toward the input of the transmission. Some of this oil lubricates bearing (33) and No. 3 clutch (10). The remainder of this oil continues along center shaft (11) to the void between input shaft (30) and center shaft (11). This oil is routed to planetary gears (6) and No. 2 clutch (7). This oil also flows through center shaft (11) to bearing (36). The oil that is routed toward the output of the transmission lubricates the following components:
- Bearing (35)
- Balance piston for No. 4 clutch (37)
- Planetary gears (17)
- Planetary gears (20)
- Planetary gears (24)
- Planetary gears (27)
The balance of the oil from passage (34) is routed rearward through the clutch housings. This oil lubricates No. 5 clutch (16), No. 6 clutch (19) and No. 7 clutch (22).
Operation of the Balance Pistons in the Rotating Clutches
The oil that flows to balance piston (32) for the No. 2 clutch and balance piston (37) for the No. 4 clutch is used to balance the force of the oil. The force of the oil (centrifugal force) is caused by the rotation of the No. 2 clutch (7) and the No. 4 clutch (13). The centrifugal force of the oil behind the clutch piston in the rotating clutches causes a small amount of clutch engagement (clutch drag) in the rotating clutch. The force of the oil that is behind the balance piston balances the centrifugal force of the oil that is on the clutch piston. The force of the oil that is behind the balance piston can also remove the centrifugal force of the oil that is on the clutch piston.
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| Illustration 18 | g03426072 |
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(1) Engine output speed sensor
(2) Transmission intermediate speed sensor (3) Torque converter output speed sensor (4) Transmission output speed sensor 1 (5) Transmission output speed sensor 2 (6) Transmission ECM | |
The Transmission ECM on the K Series Scraper is equipped with five speed sensors. Each speed sensor supplies a frequency input to the "Transmission ECM". Each of the speed sensors is attached to the transmission with a fixed mount. No adjustment of the mount for the speed sensor is necessary.
The speed sensors produce a signal that varies in frequency (Hz) as the tooth of the gear is passed in front of the sensor. Each tooth that passes the gear will produce one cycle or hertz of the frequency signal. The ECM detects the frequency of the signal. The ECM then determines the speed and the direction of the gear and the shaft that the gear is mounted on. Each speed sensor has two input connections to the ECM (+ and -). On all the speed sensors, connector contact 2 is the signal (+). Connector contact 1 is the return line (-).
The "Transmission ECM" monitors the two output speed sensors. The output speed sensors are used to determine the transmission output speed (TOS) and the direction of travel. If the TOS or direction signals are faulty, the ECM uses the signal from the intermediate speed sensor to determine these factors. The intermediate speed sensor is then used to calculate the TOS and to determine the direction. As a result, the ECM will maintain control of the transmission if a failure of the two output speed sensor circuits occurs. At the lower transmission output speed, the slower speed of the output gear results in a poor signal from the output speed sensors. The larger intermediate gear is rotating faster at the lower output shaft speed which results in a more reliable intermediate speed sensor signal.
The ECM uses the transmission output speed and direction data to control the shifting of the transmission. The ECM will use the transmission output speed and direction information to control the operation of the transmission and to prevent unsafe operating conditions.
The intermediate speed sensor is monitoring one intermediate gear in the transmission. Both of the output speed sensors are monitoring individual output gears in the transmission. The "Transmission ECM" expects approximately the same signal to be coming from each the pairs of speed sensors. If the signals differ more than 50 Hz, the ECM will determine the correct signal. The determination is based on the input signals from the other speed sensors on the transmission. Then, the ECM will activate a diagnostic code for the speed sensor circuit that has the abnormal condition.
Transmission Shift Lever Sensor
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| Illustration 19 | g03426908 |
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(1) Transmission ECM J2
(2) Transmission ECM J1 (3) Transmission shift lever | |
The ECM must know the current gear position. The sensor for the shift lever provides a pulse width modulation (PWM) signal. The PWM signal varies with the gear that is selected.
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| Illustration 20 | g03645287 |
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(1) Transmission ECM
(2) Engine retarder control lever (3) Engine ECM (4) Compression brake solenoid 1 and 2 (5) Compression brake solenoid 3 and 4 (6) Compression brake solenoid 5 and 6 | |
The engine retarder lever has four positions, OFF, LOW, MEDIUM, and HIGH. In the OFF position, there is not a complete circuit and the machine operates normally. In the LOW, MEDIUM, and HIGH positions, the corresponding circuit will be completed. This will send a signal over the CAN network to the engine ECM (3), which then will active the corresponding compression brake solenoids (4), (5), and (6). With the lever in the LOW position, the compression brake solenoid for cylinders 3 and 4 is activated. With the lever in the MEDIUM position, the compression brake solenoids for cylinders 1, 2, 5, and 6 are activated. With the lever in the HIGH position, all of the compression brake solenoids are active.
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| Illustration 21 | g03645919 |
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(1) Transmission ECM
(2) Left wheel speed sensor (3) Right wheel speed sensor (4) Accelerometer | |
The tire spin reduction system provides two main functions.
- Reducing tire slip on uneven ground surfaces.
- Protecting the jaw type differential lock from possible damage.
The wheel speed sensors (2) and (3) constantly monitor the rotational speeds of each wheel. This information is compared to an accelerometer on the machine. If the data from the wheel speed sensors does not match information from accelerometer (4), the engine ECM will change fuel maps until the wheel speeds align themselves.
The wheel speed sensors are also used to ensure that the speed differential between the wheels is at a minimum before the No-Spin locking differential can be engaged. This action helps to prolong the life of the locking differential.