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| Illustration 1 | g00771976 |
Transmission Hydraulic Schematic (The Transmission is in NEUTRAL and the Engine is Stopped.) (1) Number 2 Clutch Solenoid (2) Number 3 Clutch Solenoid (3) Priority Valve (4) Number 1 Clutch Solenoid (5) Number 5 Clutch Solenoid (6) Number 4 Clutch Solenoid (7) Flow Control Orifice (8) Modulating Valve for the Lockup Clutch (9) Modulating Valve for the Impeller Clutch (10) Slug (11) Converter Inlet Ratio Valve (12) Slug (13) Modulating Relief Valve (14) Direction Selection Spool (15) Torque Converter (16) Lockup Clutch (17) Impeller Clutch (18) Selector Spool (First Speed and Third Speed) (19) Pressure Differential Valve (20) Load Piston (21) Load Piston Orifice (22) Selector Spool (Second Speed) (23) Power Train Oil Filter for the High Pressure Circuit (24) Power Train Oil Filter for the Low Pressure Circuit (25) Torque Converter Bypass Orifice (26) Power Train Oil Pump (27) Torque Converter Outlet Relief Valve (28) Power Train Oil Cooler (29) Magnetic Screen (30) Lubrication Passage for Transmission (31) Reservoir (32) Reservoir (A) Pressure Tap for the Main Relief Valve (B) Pressure Tap for the Priority Valve (C) Pressure Tap for Lockup Clutch (D) Torque Converter Inlet Pressure Tap P3 (E) Speed Clutch Pressure Tap P1 (F) Pressure Tap for Impeller Clutch (G) Direction Clutch Pressure Tap P2 (H) Pump Pressure Tap (I) Torque Converter Outlet Pressure Tap (J) Transmission Lubrication Pressure Tap | |
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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. Prevent possible injury by performing the procedure that follows before working on the machine. |
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| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates. |
- Move the machine to a smooth, horizontal location that is away from operating machines and away from personnel.
Note: Permit only one operator on the machine. Keep all other personnel away from the machine or in the operators sight.
- Move the STIC transmission direction control switch to the NEUTRAL position.
- Lower the work tool to the ground.
- Engage the parking brake.
- Place blocks in front of the wheels and behind the wheels.
- Install the steering frame lock.
- Remove the front axle shafts and the rear axle shafts except for the stall tests.
- Allow only authorized personnel on the machine. Keep unauthorized personnel off the machine and in clear sight of the operator.
Note: All tests and all adjustments must be made while the transmission oil is at normal operating temperature.
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The input drive shaft rotates between the torque converter and the transmission whenever the engine is running. Contact with the rotating shaft can result in personal injury or death. The rotating shaft is located under the door assemblies that are behind the machine cab. Do not allow personnel into the area behind the cab when the machine is running. |
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| NOTICE |
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Do not connect or disconnect hose fittings to or from the quick disconnect nipples when there is pressure in the system. This will prevent damage to the seals that are in the fitting. |
| Required Tools | ||
| Part Number | Description | Quantity |
| 1U-5481 | Pressure Gauge Group | 1 |
| 1U-5482 | Pressure Adapter Group | 1 |
Test Procedures
| Transmission Speed Selection | Engaged Clutches |
| Third Speed Forward | Number 2 and Number 3 |
| Second Speed Forward | Number 2 and Number 4 |
| First Speed Forward | Number 2 and Number 5 |
| Neutral | Number 3 |
| First Speed Reverse | Number 1 and Number 5 |
| Second Speed Reverse | Number 1 and Number 4 |
| Third Speed Reverse | Number 1 and Number 3 |
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| Illustration 2 | g00740476 |
(D) Torque Converter Inlet Pressure Tap P3. (E) Speed Clutch Pressure Tap P1. | |
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| Illustration 3 | g00740501 |
Transmission (D) Torque Converter Inlet Pressure Tap P3. (E) Speed Clutch Pressure Tap P1. (G) Direction Clutch Pressure Tap P2. (J) Transmission Lubrication Pressure Tap. | |
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| Illustration 4 | g00453841 |
Power Train Oil Filters "PT OIL FLTR PLGD" will be displayed on the Vital Information Management System (VIMS) if the filter becomes plugged. (H) Pressure tap for the power train oil pump. (The pressure tap is located on the left side of the machine.) | |
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| Illustration 5 | g03665375 |
Transmission Selector and Pressure Control Valve The transmission selector and pressure control valve is on the top of the transmission. The transmission cover is removed. (L) Plug for Load Piston LP. | |
- Install the correct hose assembly from 1U-5482 Pressure Adapter Group on the following pressure taps: (E) , (G) and (H) . Attach the opposite end of the hose assembly to the 0 to 3400 kPa (0 to 580 psi) pressure gauge in the 1U-5481 Pressure Gauge Group .
- Engage the parking brake. Shift the STIC transmission direction control switch to the NEUTRAL position. Shift the transmission to first speed. Start the engine and operate the engine at low idle.
- Depress the right service brake pedal and hold the right service brake pedal. Release the parking brake. Watch the pressure gauges. Shift the STIC transmission direction control switch from the NEUTRAL position to the FORWARD position. Increase the engine speed to high idle. Make sure that the transmission oil is at normal operating temperature. The needle on the pressure gauge for the Number 2 clutch should rise. The needle on the pressure gauge for the Number 5 clutch should rise. The pressure readings must be within the values that are found in Table 3.
With the transmission in the FORWARD position, shift through the remaining forward speeds and return to the FIRST SPEED position. The pressure reading for each clutch that is energized must be within the values that are found in Table 3. This checks the pressure of all the speed clutches.
- Perform Step 3 for all reverse speeds. The same pressure levels should be noted in all reverse speeds.
Test for the Lubrication Oil Pressure
Use the following procedure to check the pressure of the transmission lubrication oil.
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| Illustration 6 | g00454785 |
(J) Transmission Lubrication Pressure Tap. The pressure tap is located on the rear of the transmission case toward the front of the machine. | |
- Install the correct hose assembly from 1U-5482 Pressure Adapter Group on pressure tap (J) . Attach the opposite end of the hose assembly to the 0 to 400 kPa (0 to 58 psi) pressure gauge in the 1U-5481 Pressure Gauge Group .
- Start the engine and operate the engine at high idle. Observe the pressure gauge. With the oil at normal operating temperature, the lubrication oil pressure must be within values that are found in Table 3.
Transmission Pressures
| Transmission Pressure | ||||
| Pressure | Pressure Tap | Pressure at Low Idle | Pressure at High Idle | Adjustment |
| Oil Pump | (H) | This pressure is identical to speed clutch pressure P1. | This pressure is identical to speed clutch pressure P1. | - |
| Speed Clutch P1 | (E) | This pressure must not be more than 480 kPa (70 psi) below the pressure at high idle. Plug (L) for the load piston is installed. |
This pressure is 2650 ± 135 kPa (385 ± 20 psi) when the direction switch is in FORWARD or in REVERSE and any speed is selected. Plug (L) for the load piston is installed. |
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| Direction Clutch P2 | (G) | This pressure is 2140 ± 170 kPa (310 ± 25 psi). Plug (L) for the load piston is installed. |
This pressure is 2230 ± 170 kPa (325 ± 25 psi). Plug (L) for the load piston is installed. |
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| Transmission Lubrication Oil | (J) | - | This pressure is approximately 170 kPa (25 psi). |
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Adjustments for the Transmission Pressures
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| Illustration 7 | g00449583 |
Transmission Selector and Pressure Control Valve (20) Load piston. (34) Spacers. | |
| Pressure Change for the Valve (1) | |||
| Description | Thickness | Pressure Change | Location of Spacers |
| 5M-9622 Spacer (34) | 1.58 mm (.062 inch) |
98 kPa (14.2 psi) |
Load Piston (20) |
| 5M-9623 Spacer (34) | 0.91 mm (.036 inch) |
57 kPa (8.20 psi) |
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| 5M-9624 Spacer (34) | 0.25 mm (.010 inch) |
16 kPa (2.29 psi) |
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| ( 1 ) | Result of the addition of one spacer or the removal of one spacer to the valve. |