2005/12/19 Caterpillar

Correction to Testing and Adjusting, "Transmission Pressures - Test and Adjust" {3030}

Usage:

834G BPC

Landfill Compactor: 836G (S/N: BRL1-UP)
Wheel Dozer: 834G (S/N: BPC1-UP)

Testing and Adjusting, RENR2182-09, "834G Wheel Dozer and 836G Landfill Compactor Power Train", "Transmission Pressures - Test and Adjust". This module is part of Service Manual, RENR2175. Disregard this article. Replace this article with the following information.

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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

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.

Park the machine on a smooth, level surface.
Shift the transmission direction control switch to the NEUTRAL position.
Lower the blade or 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 rear axle shafts except for 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 when transmission oil is at normal operating temperature.

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NOTICE

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.

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Table 1
Required Tools
Part Number	Description	Qty
1U-5481⁽¹⁾	Pressure Gauge Group	1
1U-5482	Pressure Adapter Group	1

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⁽¹⁾	The 198-4240 Pressure Indicator Tool Gp is also available.

Test Procedures

Test for the Modulating Valves for the Transmission Clutches

This test will determine whether the solenoid coil is energized and the solenoid plunger is shifting to permit the flow of oil through the modulating valve for the transmission clutch.

Hearing the click of a solenoid or using a screwdriver to check that the solenoid coil is energized does not ensure that the solenoid plunger has shifted. The following test will determine if the solenoid plunger is shifting.

The direction clutch pressure taps and the speed clutch pressure taps are installed in the modulating valves for the transmission clutches. The modulating valves for the transmission clutches are on the top of the transmission beneath the cab.

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Table 2
Speed Range and Direction	Engaged Clutches and Energized Solenoids
Fourth Speed Forward	3 and 2
Third Speed Forward	4 and 2
Second Speed Forward	5 and 2
First Speed Forward	6 and 2
Neutral	3
First Speed Reverse	6 and 1
Second Speed Reverse	5 and 1
Third Speed Reverse	4 and 1

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Illustration 1	g00618128
Modulating valves for the transmission clutches (A) Number 5 clutch pressure tap (B) Number 6 clutch pressure tap (C) Number 3 clutch pressure tap (D) Number 1 clutch pressure tap (E) Number 4 clutch pressure tap (F) Number 2 clutch pressure tap

Install the correct hose assembly from the 1U-5482 Pressure Adapter Group on pressure tap (A) through pressure tap (F). Attach the opposite end of the hose assembly to the 0 kPa to 3400 kPa (0 psi to 580 psi) pressure gauge in the 1U-5481 Pressure Gauge Group.
Engage the parking brake. Shift the transmission direction control switch to the NEUTRAL position. Start the engine and operate the engine at low idle.
Depress the right service brake pedal and hold the right service brake pedal. Make sure that the machine is in FIRST SPEED. Release the parking brake. Watch the pressure gauges. Shift the transmission direction control switch from the NEUTRAL position to the FORWARD position.
The needle on the pressure gauge for the Number 2 clutch should rise. The needle on the pressure gauge for the Number 6 clutch should rise. With the transmission in the FORWARD position, shift through the remaining forward speeds and return to the FIRST SPEED position. Use the transmission upshift switch to change speeds. The same pressure rise should be observed in each respective speed. Observe the operation of all the speed clutches.
Perform Step 3 for all reverse speeds. The same pressure rise should be noted in all reverse speeds.

If a pressure rise is noted, the solenoid and the related electrical circuit are functioning.

If a pressure rise is not noted, use a screwdriver to check that the solenoid coil is energized. If the screwdriver is attracted to the solenoid coil, indicates that the solenoid coil is energized. The problem is in the solenoid cartridge. The problem could be a bent solenoid stem, a screen that is dirty or plugged, or a spring that is weak or broken.

If the screwdriver does not indicate that the solenoid coil is energized, the problem is in the electrical circuit.

Reference: For additional information about the modulating valves for the transmission clutches, refer to the Service Manual module Systems Operation, "Modulating Valve (Transmission Clutch)" for the machine that is being serviced.

Reference: For additional information about calibrating the modulating valves for the transmission clutches, refer to the Service Manual module Testing and Adjusting, "Calibration" for the machine that is being serviced.

Reference: For additional information about electrical system troubleshooting, refer to the Service Manual module Testing and Adjusting, "Diagnostic Code List" for the machine that is being serviced.

Pressure Test for Transmission Clutch

Use the following procedure to check the pressure of the direction clutch oil and the speed clutch oil.

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Illustration 2	g00618128
Modulating valves for the transmission clutches (A) Number 5 clutch pressure tap (B) Number 6 clutch pressure tap (C) Number 3 clutch pressure tap (D) Number 1 clutch pressure tap (E) Number 4 clutch pressure tap (F) Number 2 clutch pressure tap

Install the correct hose assembly from the 1U-5482 Pressure Adapter Group on pressure tap (A) through pressure tap (F). Attach the opposite end of the hose assembly to the 0 kPa to 3400 kPa (0 psi to 580 psi) pressure gauge in the 1U-5481 Pressure Gauge Group.
Engage the parking brake. Shift the transmission direction control switch to the NEUTRAL position. 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. Make sure that the machine is in first speed. Watch the pressure gauges. Shift the 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 6 clutch should rise. The pressure readings must be within the values in Table 3.
With the transmission in the FORWARD position, shift through the remaining forward speeds and return to the FIRST SPEED position. Use the upshift switch to change speeds. The pressure reading for each energized clutch must be within the values in Table 3. Observe 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.

Pressure Adjustment for Transmission Clutch

If the pressure reading for each energized clutch is not within the values in Table 3, the modulating valve for the transmission clutch may need to be calibrated.

Reference: For more information, refer to the Calibration for the Transmission Clutch Engagement in the Service Manual module Testing and Adjusting, "Calibration" for the machine that is being serviced.

Pressure Test for Lubrication Oil

Use the following procedure to check the pressure of the transmission lubrication oil.

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Illustration 3	g00682799

The inlet for the transmission lubrication oil is on the left side of the machine.

Install the correct hose assembly from the 1U-5482 Pressure Adapter Group on pressure tap (G). Attach the opposite end of the hose assembly to the 0 kPa to 400 kPa (0 psi 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 the values in Table 3.

Pressure Test for Torque Converter Outlet

Use the following procedure to check oil pressure at the torque converter outlet.

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Illustration 4	g00624203

The torque converter outlet is on the left side of the machine on the torque converter housing.

Install the correct hose assembly from the 1U-5482 Pressure Adapter Group on pressure tap (H). Attach the opposite end of the hose assembly to the 0 kPa to 1000 kPa (0 psi to 145 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 torque converter outlet pressure must be within the values in Table 3.

Pressure Test for Transmission Oil Pump

Use the following procedure to check transmission oil pump pressure.

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Illustration 5	g00624235

The transmission hydraulic control relief valve is on the left side of the machine on the torque converter housing.

Install the correct hose assembly from the 1U-5482 Pressure Adapter Group on pressure tap (K). Attach the opposite end of the hose assembly to the 0 kPa to 3400 kPa (0 psi to 580 psi) pressure gauge in the 1U-5481 Pressure Gauge Group.
Start the engine and operate the engine at high idle. Observe the pressure gauges. With the oil at normal operating temperature, the transmission oil pump pressure must be within the values in Table 3.

Pressure Test for Torque Converter Inlet

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Illustration 6	g00624354

The transmission hydraulic control relief valve is on the left side of the machine on the torque converter housing.

Install the correct hose assembly from the 1U-5482 Pressure Adapter Group on pressure tap (L). Attach the opposite end of the hose assembly to the 0 kPa to 2000 kPa (0 psi to 290 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 torque converter inlet pressure must be within the values in Table 3.

Transmission Pressures

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Table 3
Transmission Pressures⁽¹⁾
Pressure Tap	Specification	Actual Pressure
(D) Number 1 clutch pressure	2210 ± 70 kPa (320 ± 10 psi)
(F) Number 2 clutch pressure	2210 ± 70 kPa (320 ± 10 psi)
(C) Number 3 clutch pressure	2275 ± 70 kPa (330 ± 10 psi)
(E) Number 4 clutch pressure	2275 ± 70 kPa (330 ± 10 psi)
(A) Number 5 clutch pressure	1725 ± 70 kPa (250 ± 10 psi)
(B) Number 6 clutch pressure	2275 ± 70 kPa (330 ± 10 psi)
(G) Transmission lubrication pressure (80° C to 85° C oil)	Low idle 20 kPa (3.0 psi) High idle 150 kPa (22 psi)
(H) Torque converter outlet pressure (80° C to 85° C oil)	Low idle 370 kPa (54 psi) High idle 420 kPa (61 psi)
(K) Transmission oil pump pressure (80° C to 85° C oil)	Low idle 2800 kPa (406 psi) High idle 3200 kPa (464 psi)
(L) Torque converter inlet pressure (80° C to 85° C oil)	Low idle 390 kPa (57 psi) High idle 550 kPa (80 psi)