Is oil leaking excessively past the control valve spool?
YES - Replace Directional Control Valve (DCV) bank (TM 5-2350-262-20).
NO - Go to Step (4).
Perform HDC system solenoid valve V20 test.
Reset all HDC solenoid valves by selecting RESET VALVES button (Figure 4, Item 5) on HDC control
Start engine and leave it running.
Wait until transducer T-13 hydraulic pressure on HDC display (Figure 4, Item 1) is greater than 2,000 psi
Using LINE UP or LINE DOWN button (Figure 4, Item 3), select V12 on HDC display (Figure 4, Item 2).
Close V12 on HDC display (Figure 6, Item 2), by selecting CHANGE POSITION button
(Figure 6, Item 4) on HDC control box.
Allow hydraulic pressure to stabilize for thirty seconds, then time the pressure loss for one minute at
Figure 4. Hydraulic Diagnostic Center (HDC) Control Box.
If pressure loss is greater than 100 psi (690 kPa) per minute, solenoid valve V20 is leaking.
Stop engine and relieve hydraulic pressure.