797 Off-Highway Truck Power Train Caterpillar

Create a Test Group on Caterpillar Electronic Technician (ET)

1. On the ET screen toolbar, click File - Select ECM, and choose Transmission ECM.

2. In the status group, create a new group name entitled "797 Transmission Test".

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Illustration 1	g00984088

3. Select the items on the ET screen above, as shown in Illustration 1.

Test 1: Transmission Test

Perform the transmission tests that are listed in Table 1.

1. Run the engine at LOW IDLE and record the data into the chart. Run the engine at HIGH IDLE and record the data into the chart.
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   Table 1

   TEST	SPECS	ACTUAL
   Transmission Oil Temperature (during tests)	> 80 °C (175 °F) < 121 °C (250 °F)
   Transmission Charging Filter Restriction	Max restriction 345 ± 21 kPa (50 ± 3 psi)	Low idle: High idle:
   Transmission Charging Pressure (Main Relief)	Low idle 2310 ± 138 kPa (335 ± 20 psi) High idle 2650 ± 138 kPa (385 ± 20 psi)	Low idle: High idle:
   Transmission Clutch Latching Pressure (1)	Low idle: 2206 ± 138 kPa (320 ± 20 psi) High idle: 2482 ± 138 kPa (360 ± 20 psi)	Low idle: High idle:
   Transmission Lubrication Oil Pressure at Rear Transmission Module  (2)	Low idle 105 ± 35 kPa (15 ± 5 psi) High idle 480 ± 100 kPa (70 ± 15 psi)	Low idle: High idle:
   Transmission Lubrication Oil Pressure at Front Transmission Module  (3)	Low idle 55 kPa to 95 kPa (8 psi to 14 psi) High idle 380 kPa to 550 kPa (55 psi to 80 psi)	Low idle: High idle:
   Transmission Lubrication Oil Pressure - Clutch 6 and 7 at Rear Transmission Module  (4) (5)	Low idle 62 ± 14 kPa (9 ± 2 psi) High idle 345 ± 70 kPa (50 ± 10 psi)	Low idle: High idle:

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   ( 1 )	At pressure tap
   ( 2 )	At sensor location
   ( 3 )	At front transmission module pressure tap
   ( 4 )	At bottom of lube valve
   ( 5 )	Transmissions equipped with an updated lubrication manifold will see reduced lube pressure for clutches 6 and 7. For transmissions with an updated lubrication manifold, no lube test is now required for clutches 6 and 7.

Test 2: Transmission Clutch Pressure Test at LOW IDLE

This test is conducted while in CONVERTER DRIVE.

1. Connect 0 to 4135 kPa ((0 to 600 psi)) gauges to the clutches that are being tested. Refer to Table 2.

2. Run the engine at LOW IDLE. Apply the parking brakes and the service brakes when the transmission is in a gear.

3. Record the pressures in Table 2.

4. If the clutch pressure is out of specification, proceed to "Test 3: Transmission Clutch Calibrations".
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   Table 2

   CLUTCH PRESSURE AT LOW IDLE
   CLUTCH	CONVERTER DRIVE	ACTUAL	GEAR	CLUTCHES ENGAGED
   2	2067 ± 138 kPa (300 ± 20 psi)		NEUTRAL	2
   2	2067 ± 138 kPa (300 ± 20 psi)		REVERSE	2 - 7
   3	2067 ± 138 kPa (300 ± 20 psi)		FIRST	3 - 6
   6 (1)	2310 ± 138 kPa (335 ± 20 psi)		FIRST	3 - 6
   7 (2)	2310 ± 138 kPa (335 ± 20 psi)		REVERSE	2 - 7
   Transmission Oil Temperature (during tests)			> 80 °C (175 °F) < 121 °C (250 °F)

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   ( 1 )	Clutch 6 is limited by pump pressure in CONVERTER DRIVE
   ( 2 )	Clutch 7 is limited by pump pressure in CONVERTER DRIVE

Test 3: Transmission Clutch Calibrations

Illustration 2	g00984086

The following two transmission clutch calibrations can be performed:

• Transmission Clutch Engagement Pressure Calibration

• Transmission Fill Calibration

Procedure for Transmission Clutch Engagement Pressure Calibration

This test in conducted at LOW IDLE

1. Connect 0 to 4135 kPa (0 to 600 psi) gauges to the clutches that are being tested.

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Illustration 3	g00984087

2. On the ET screen toolbar, click Service - Calibration - Transmission Clutch Engagement Pressure Calibration. The screen in Illustration 3 will appear.

   Note: All of the boxes are selected by default.

3. Unselect the boxes of the clutches that are not being tested.

   Note: Leave the box for the "Lockup Clutch Engagement Pressure Calibration" selected at all times.

4. Select the "Begin" button and the screen in Illustration 4 will appear.

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Illustration 4	g00984089

Note: The bottom arrow keys are not selectable at this point.

5. When the setup calibration conditions are met, select the "Next" button in order to continue.

6. Observe the pressure gauges of the clutches that are being tested.

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Illustration 5	g00984084

7. Refer to Illustration 5. Notice that the bottom arrow keys are now selectable. If the clutch pressure is not within specification, use these arrow keys in order to adjust the current to the clutch solenoid. This will increase the clutch pressure or decrease the clutch pressure.

   Note: The single arrows at the bottom of the screen change the clutch pressure by 7 kPa (1 psi). The double arrows at the bottom of the screen change the clutch pressure by 70 kPa (10 psi).

8. The clutch pressure is set through the transmission software. View the pressure through ET. The target value for calibration is the value stated in the software ± 35 kPa (5 psi).

9. Select the "Next" button, and the screen in Illustration 6 will appear.

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Illustration 6	g00984085

10. The screen in Illustration 6 will show whether the calibration was a SUCCESS or was NOT SUCCESSFUL.

Procedure for Transmission Fill Calibration

Note: Caterpillar Electronic Technician (ET) conducts this test automatically.

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Illustration 7	g00984083

1. On the ET screen toolbar, click Service - Calibration - Transmission Fill Calibration. The screen in Illustration 7 will appear.

2. When the setup calibration conditions are met, select the "Next" button in order to continue.

3. Engine speed will vary as each clutch is selected for calibration starting with clutch 1.

   Note: One or two clutches will be simultaneously engaged in order to provide a load to the clutch that is being calibrated.

4. The clutch that is being calibrated will engage and disengage several times, until the Transmission ECM is satisfied that the clutch fill calibration is complete.

5. The calibration process will continue until all of the clutches have been calibrated, or until the user aborts by choosing the "Cancel" button.

   Note: The transmission fill calibration procedure will abort automatically if any of the setup calibration conditions are changed, or go out of range.

The transmission fill calibration procedure will take between 30 to 45 minutes in order to complete (approximately 4 minutes per clutch).