420D, 428D, 430D, 432D, 438D and 442D Backhoe Loaders Transmission (Autoshift) Caterpillar

Use the following assembled hose group to perform your tests.

1. Install one 6V-4143 Coupler onto each end of 6V-3014 Hose Assembly .

2. Install one 6V-3989 Unvalved Nipple onto each pressure gauge.

3. Connect one of the 6V-3014 Hose Assembly to each of the pressure gauges.

4. Some of the 6V-3965 Fitting As must be installed into the transmission.

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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before the test is done.

Note: For all tests, the machine must be at operating temperature.

The following components must be removed before the transmission system can be tested.

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Illustration 1	g00759467

1. Remove ten bolts (2) and cover (1) .

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Illustration 2	g00759476

2. Remove two bolts (3) and plate (4) .

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Illustration 3	g00759478

3. Remove two bolts (5) and plate (6). Remove floormat (7) .

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Illustration 4	g00759487

4. Remove four bolts (8) and set the floorplate (9) aside.

5. Proceed to the appropriate test that is required. Reinstall the plates, screws and the mats to the cab when testing is completed.

Test for the Transmission Oil Pump Pressure

This test will show if the transmission oil pump is good.

Illustration 5	g00760132

1. At pressure tap (1), connect a hose group with a 4000 kPa (600 psi) pressure gauge to the fitting at the pressure tap.

2. Place the direction control lever in NEUTRAL. Also place the speed shift lever in NEUTRAL.

3. Activate the parking brake. Start the engine and run the engine at low idle.

4. Shift the direction control lever to FORWARD and the speed shift lever in NEUTRAL. Run the engine at high idle. The pressure on the gauge must be 1450 ± 100 kPa (210 ± 15 psi).

5. When this test is complete, reduce the engine speed to low idle. Place the forward/reverse shuttle in NEUTRAL. Stop the engine and remove the equipment.

Test for the Torque Converter Outlet Pressure

The test will show if engine performance is good. The test will show if the torque converter operates properly. Also, the test will show if there is oil flow through the oil cooler.

Note: Any unusual noises during this check should be noted. Loud noises could indicate that repairs are needed.

1. Start the engine.

2. Lower the stabilizers and lift the rear wheels about 150 mm (6 inch) off the ground.

3. Place the bucket hydraulic controls in the lowering position. Lift the front wheels about 150 mm (6 inch) off the ground.

4. The engine speed needs to be at low idle during these previous steps.

5. Stop the engine and proceed with the following procedure.

1. Install the 6V-3121 Multitach on the engine. The multitach can measure engine speed by the use of a photo pickup and reflective tape. The Special Instructions, SEHS7807 has instructions for the use of the multitach.

2. With the transmission shift lever in (NEUTRAL) position, start the engine and run the engine at low idle. Ensure that high idle rpm and low idle rpm are correct. Refer to Engine supplement, SENR5815, "3054 Engines for Caterpillar Built Machines".

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NOTICE
To ensure that the transmission oil does not overheat, do not keep the torque converter in a full stall condition for more than 30 seconds. After the torque converter stall test, reduce the engine speed to low idle. In order to cool the oil, move the transmission control to the NEUTRAL position and run the engine between 1200 rpm and 1500 rpm.

3. Run the engine at high idle. Fully engage the brakes. Run the transmission at normal operating temperature 59 to 71°C (138 to 160°F). Shift to FOURTH SPEED. Shift the forward/reverse shuttle to FORWARD and stall the torque converter until the converter temperature reaches 90 to 93°C (194 to 200°F). The stall speed should match the chart.

   Note: The following chart is for the rpm of the torque converter stall. The chart is based on using field fuel. Factory fuel may cause the rpm to be lower than the numbers that are indicated in the chart.

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   Table 2

   Horsepower Rating	Stall RPM
   75 hp	1975 ± 75 RPM
   80 hp	2050 ± 75 RPM
   85 hp	2075 ± 75 RPM
   93 hp	2160 ± 75 RPM

   Note: Stall speeds are calculated using No. 2 diesel fuel.

4. When the test is complete, put the forward/reverse shuttle in NEUTRAL and the shift lever in NEUTRAL. Stop the engine and remove the test equipment.

Note: Do not keep the torque converter in a stall condition for very long periods of time. The torque converter, the engine, and the brakes will get hot.

Problem

The oil gets too hot during normal operation.

Probable cause

1. Not enough oil is in the torque converter because the inlet relief valve for the torque converter is open.

2. The oil pump fails.

3. The torque converter fails.

4. The temperature gauge is bad. Replace the temperature gauge and the sending unit.

5. Debris is blocking the air flow to the oil cooler. Debris could also be blocking air flow to the engine cooler.

Problem

Torque converter outlet pressure is too high.

Probable cause

1. There is too much restriction in the oil cooler or the oil cooler lines.

Problem

Stall speed is low, but torque converter outlet pressure is correct.

Probable cause

1. There is an engine problem.

2. The machine is using factory fuel.

3. There is a problem with the torque converter.

Forward Clutch Pressure and Reverse Clutch Pressure and Transmission Lubrication

This test will show if the oil pressure to the following clutches is good: forward high clutch, forward low clutch, clutch 1, clutch 2, clutch 3 and reverse clutch. The test will also show if the oil pressure to the transmission lubrication circuit is good.

1. Install the 6V-3121 Multitach on the engine. The 6V-3121 Multitach can measure the engine speed by the use of the photo pickup and the reflective tape. The instructions for the use of the photo pickup and reflective tape are in Special Instruction, SEHS7807.

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Illustration 6	g00760133
Pressure tap locations (1) Clutch 1 (2) Lube and cooling (3) Reverse clutch (4) Forward low clutch (5) Forward high clutch (6) Clutch 2 (7) Clutch 3

2. The following pressure taps connect a hose group with a 4000 kPa (580 psi) pressure gauge to the fitting at the pressure tap: (1), (3), (4), (5), (6) and (7) .

3. The pressure tap (2) connects a hose group with a 400 kPa (58 psi) pressure gauge to the fitting at the pressure tap.

4. Start the engine and run the engine at low idle.

5. With the transmission gear selector in NEUTRAL, shift the direction control lever to FIRST SPEED FORWARD. The pressure on the gauge for the forward low clutch must be 1325 ± 225 kPa (190 ± 30 psi). The pressure on the clutch 1 must be 1375 ± 225 kPa (200 ± 30 psi). The lubrication gauge must be 50 ± 25 kPa (10 ± 5 psi).

6. Shift the direction control lever to SECOND SPEED FORWARD. The pressure on the gauge for the forward high clutch must be 1325 ± 225 kPa (190 ± 30 psi). The pressure on the clutch 1 must be 1375 ± 225 kPa (200 ± 30 psi).

7. Shift the direction control lever to THIRD SPEED FORWARD. The pressure on the gauge for the forward high clutch must be 1325 ± 225 kPa (190 ± 30 psi). The pressure on the clutch 2 must be 1475 ± 225 kPa (215 ± 30 psi).

8. Now shift the direction control lever to THIRD SPEED REVERSE. The reverse clutch pressure must be 1325 ± 225 kPa (192.1780 ± 32.6340 psi) of the pressure in the FORWARD at the same engine speed. The lubrication gauge must be 170 ± 70 kPa (25 ± 10 psi). The gauge for the forward clutch must read 0 kPa (0 psi).

9. When the test is complete, put the direction control in NEUTRAL, and engage the parking brakes. Stop the engine. Remove the test equipment.

Problem

Both forward clutch pressure and reverse clutch pressure is too low.

Probable Cause

1. The spring to the system relief valve is weak.

2. The oil level is low.

3. The oil filter is plugged. Replace the dirty oil filter.

4. Oil pump failure.

5. The neutralizer button that is on the shift lever or the tilt control lever shorted. This caused the solenoid control valve to de-energize.

6. The clutch piston seals are bad.

Problem

Either a forward clutch pressure or a reverse clutch pressure is too low.

Probable Cause

1. The solenoid is faulty.

2. The clutch piston seals are bad.

3. The seals are faulty or the seals are missing on the input shaft.