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Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
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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, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
Introduction
The following test procedure will check the pressure of the charge oil that is being delivered from a modulating valve (transmission) to a transmission clutch. There are nine individual modulating valves that control the nine transmission clutches. The modulating valves (transmission) are modulated. The modulation of these valves can be adjusted.
Required Tools
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| Illustration 1 | g01089423 |
Tooling (A) | |
Use the tools in Table 1 to complete the following test procedure.
| Required Tools (Pressure Gauges) | ||||
|---|---|---|---|---|
| Tool | Item | Part Number | Description | Qty |
| A | A1 | 6V-3989 | Fitting (Test) | 2 |
| A2 | 8T-0855 | Pressure Gauge | 2 | |
| A3 | 177-7861 | Hose As | 2 | |
| A4 | 6V-4143 | Coupler | 4 | |
| 143-4065 | Pressure Sensor 0 to 6895 kPa (0 to 1000 psi) |
1 | ||
Test Procedure
Pressure gauges are used in the following test procedure.
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| Illustration 2 | g01325496 |
Transmission Clutches | |
The designated letters are used to correlate a modulating valve to the corresponding transmission clutch, as shown.
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| Illustration 3 | g01329199 |
Modulating Valves (Transmission) | |
Each modulating valve has a designated letter, as shown. The letters have been cast into the transmission housing.
Log the clutch pressures in Table 2. There are always two clutches that are engaged for each gear selection. NEUTRAL position only uses one clutch. See Table 2 in order to determine the clutches that are engaged for each gear selection.
| Checklist for Transmission Clutch Pressures | ||||
|---|---|---|---|---|
| Gear | Clutch or Valve | Pressure Measurement | Clutch or Valve | Pressure Measurement |
| Fourth gear (reverse) | A | J | ||
| Third gear (reverse) | A | H | ||
| Second gear (reverse) | A | B | ||
| First gear (reverse) | A | G | ||
| Neutral | J | - | - | |
| First gear | C | G | ||
| Second gear | D | G | ||
| Third gear | E | G | ||
| Fourth gear | F | G | ||
| Fifth gear | C | B | ||
| Sixth gear | C | H | ||
| Seventh gear | D | B | ||
| Eighth gear | D | H | ||
| Ninth gear | E | B | ||
| Tenth gear | E | H | ||
| Eleventh gear | F | B | ||
| Twelfth gear | F | H | ||
| Thirteenth gear | C | J | ||
| Fourteenth gear | D | J | ||
| Fifteenth gear | E | J | ||
| Sixteenth gear | F | J | ||
- Make sure that the transmission control lever is in the PARK position.
- Warm the oil to a minimum temperature of 60°C (140°F).
Third gear that uses clutches (E) and (G) is shown in the following test:
- Connect one end of Tooling (A) to the test port on valve (E). Connect one end of a second Tooling (A) to the test port on valve (G) .
- Operate the transmission in third gear at high idle.
- Observe the pressure that is being delivered to transmission clutches (E) and (G). You can use Table 2 to write down the measurement.
- Stop the engine.
- Repeat Steps 3 through 6 for the remaining reverse gears and forward gears. Use Table 2 in order to determine the combination of modulating valves that are being engaged for each gear.
- Compare the pressure measurements from all of the transmission clutches. The pressure measurement should be within 2100 ± 35 kPa (305 ± 5 psi).
- Remove Tooling (A) .
- Stop the engine.
- If the pressure is not within the specified limits, check the pressure that is being delivered by the relief valve (charge pressure).