ZF Repair Manual: ZF63IV, ZF80IV, ZF80-1IV
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Repair Manual and Spare Parts List
Section 9: Troubleshooting
Symptom
Possibly cause
Remedy
17. High oil temperature
17.1 Excessive fluid in transmission
17.2 Oil cooler is dirty
17.3 No water in circuit
17.4 Undersized cooler
17.5 Clutch is slipping
17.6 Excessive friction of the
reverse clutch
17.7 Possible bypass in the cooling
circuit
17.1 Remove excessive fluid with com-
mercial suction pump
17.2 Replace the cooler and check the
water circuit
17.3 Check the cooling circuit
17.4 Replace the cooler with a proper one
17.5 Refer to 4
17.6 Check the clutch play and the cor-
rect position of the piston
17.7 Reduce the bypass
18. Slipping clutch
18.1 Low pressure
18.2 Fluid level in transmission is low
18.3 Shift lever not properly adjusted
18.4 Trolling lever not in the detent
position
18.5 Wear on clutch discs
18.6 Piston rings in clutch are faulty
18.7 Inadmissible fluid used
18.8 Water in the fluid
18.9 Piston rings on input shaft
are faulty
18.1 Refer to 1
18.2 Refill with fluid
18.3 Regulate at the end of the way
18.4 Ajust the lever at the detent
position
18.5 Disassemble transmission, replace
clutch discs
18.6 Disassemble transmission, replace
piston rings
18.7 Drain fluid, refill with prescribed fluid
18.8 Repair leakage at cooler or replace
cooler. Change transmission fluid
18.9 Remove control block and replace
piston rings
19. Noise
- hydraulic
19.1 Oil filter is dirty
19.2 Fluid level in transmission is low
19.3 Oil suction hose not properly
adjusted
19.4 Defective cover filter : air suction
- at idle speed
19.5 Coupling
- under load
19.6 Wrong shimming
19.7 Defective gears
19.1 Replace oil filter
19.2 Refill with fluid
19.3 Replace the seal and adjust
correctly the suction hose
19.4 Replace cover filter
19.5 Replace
19.6 Re-shim
19.7 Replace defective gears
20. Engagement not possible
20.1 Fluid level in transmission is low
20.2 Fine filter is dirty
20.3 Incorrect shift lever position
20.4 Coupling is damaged
20.5 Control block
20.6 Shifting lever is loose
20.7 Low pressure
20.1 Refill with fluid
20.2 Replace fine filter
20.3 Regulate at the end of the way
20.4 Replace coupling
20.5 Replace control block
20.6 Tighten clamping bolt on
shifting lever
20.7 Refer to 1
21. Slow engagement
21.1 Fluid level in transmission is low
21.2 Shift lever
21.3 Regulate
21.1 Refill with fluid
21.2 Low pressure
21.3 Refer to 1
22. Hard shifting
22.1 Shift lever
22.2 Control block is dirty
22.1 Regulate
22.2 Disassemble the control valve and
clean