300Tdi Discovery
44
AUTOMATIC GEARBOX
10
FAULT DIAGNOSIS
FAULT SYMPTOMS
SYMPTOM 1 - Intermittent drive and high pitched
noise
FAULT - Low fluid level or restricted filter
SYMPTOM 2 - No drive in reverse
Select ’D’
œ No drive
FAULT - Continue with Symptom 3
œ Drives forward
FAULT - Reverse gear interlock valve
seized
Select ’1’
œ No engine braking
FAULT - Clutch brake 3
SYMPTOM 3 - No drive from rest with ’D’ selected
Select ’1’
œ Vehicle drives
FAULT - No 2 freewheel
œ No drive
Carry out main line pressure check
œ Normal pressure
FAULT - Clutch A
œ No pressure
FAULT - Blocked filter or pump failure
œ Low pressure
FAULT - Restricted filter or sticking primary
regulator
SYMPTOM 4 - Slip in all forward gears
Carry out main line pressure check
œ No pressure
FAULT - Blocked filter or pump failure
œ Low pressure
FAULT - Restricted filter or sticking primary
regulator
œ Normal pressure
FAULT - Clutch ’A’
SYMPTOM 5 - Harsh engagement ’N’ to ’D’
Check engine idle speed
Carry out main line pressure check
œ High pressure
FAULT - Primary regulator stuck
œ Normal pressure
FAULT - Clutch ’A’ or damper for clutch’A’
SYMPTOM 6 - Fierce shift or flare 1st to 2nd shift
Check engine idle speed
Carry out mainline pressure check
œ High pressure
FAULT - Continue with symptom 5
œ Normal pressure
FAULT - Modulator valve or dampers for
clutch brake CB1 and/or clutch brake CB2
FAULT - Clutch brake CB1 and/or clutch
brake CB2
SYMPTOM 7 - Fierce shift or flare 2nd to 3rd
Carry out mainline pressure check
œ High pressure
FAULT - Continue with symptom 5
œ Normal pressure
FAULT - Modulator valve or clutch ’B’
damper
FAULT - Clutch ’B’
SYMPTOM 8 - No 3rd gear
FAULT - 2-3 shift valve
FAULT - Clutch ’B’
SYMPTOM 9 - No 4th gear ’D’ selected
FAULT - 4th to 3rd downshift valve stuck or
3rd to 4th upshift valve stuck
FAULT - Clutch brake 4
