LINER AS-CAB 2742408 - Caterpillar

Illustration 4 g00552806
Pressure control valve
(2) Selector piston plugs (seven)
(3) Modulation reduction valves (seven)
(4) Load piston orifices (six)
(5) Decay orifice plugs (five)
(6) Load piston plugs (six)
(A) ( B) ( C) ( D) ( E) ( F) ( G) ( H) Pressure taps (identification for the load pistons) Use Illustration 4, Table 2, Table 3, and Table 4 for the following problems.Problem: The pressures at all the clutches are 0 kPa (0 psi).
Probable Cause
The probable cause is the pilot pressure. Perform the test in Testing and Adjusting, "Transmission Hydraulic Control Pilot Pressure - Test and Adjust".
The operation of the neutralizer valve in the selector and pressure control valve is not correct. Disassemble the selector and pressure control valve. Check for any foreign material or for any parts that are damaged or worn. Be certain that the orifice and/or the ball check valve of the neutralizer valve are free of any debris.
There is a restriction in the screen in the rotary selector spool.Problem: The pressures at all the clutches are low in torque converter drive only.
Probable Cause
The transmission gear pump is bad. Perform Testing and Adjusting, "Gear Pump (Transmission Charging) Pressure - Test and Adjust".
There is a restriction in the transmission charging hydraulic filter and/or other components.
The dual stage relief valve in the transmission selector and pressure control valve is incorrectly set. Perform Testing and Adjusting, "Gear Pump (Transmission Charging) Pressure - Test and Adjust".
There is a restriction in the screen in the rotary selector spool.Problem: The pressures at all the clutches are low in direct drive only.
Probable Cause
The pressure setting of the dual stage relief valve is incorrect. Perform Testing and Adjusting, "Transmission Hydraulic Control Dual Stage Relief Valve Pressure - Test and Adjust".
There is a restriction in the screen in the rotary selector spool.Problem: The pressure at any clutch is 0 kPa (0 psi).
Probable Cause
The selector piston is stuck.
The piston seal leaks.
The modulation reduction valve is stuck.
Selector piston plug (2) is not installed.
The supply port of the rotary selector spool is plugged.Problem: The pressure in a clutch does not increase above the primary pressure.
Probable Cause
Load piston plug (6) is not installed.
Load piston orifice (4) is plugged.Problem: The pressure in one clutch is not correct, but the primary pressure in the same clutch is correct.
Probable Cause
There are broken springs in modulation reduction valve (3).Problem: The pressure in one clutch at the high idle rpm is correct, but the pressure in the same clutch at the low idle rpm is not correct.
Probable CauseThere are bad seals in a clutch of the transmission.Problem: The pressure in one clutch does not decrease rapidly or the low pressure remains in one clutch.
Probable Cause
Decay orifice (5) is plugged.
The drain orifice in the return end of the rotary selector spool is plugged.Problem: An additional clutch receives pressure oil in certain speeds.
Probable Cause
The selector piston is stuck.
The load piston is stuck.
The modulation reduction valve is stuck.
Decay orifice (5) is plugged.
The drain orifice in the return end of the rotary selector spool is plugged.