Tread Adjust System

Symptom Problem Solution

All four tread adjusts do not function.

Load sense jamming valve not working.

See your John Deere dealer.

Speed range switch not in first.

Shift speed switch to first range.

Engine RPM's set too low.

Increase RPM's to 2600.

Fuse blown.

Replace fuse.

Faulty switch.

Replace switch.

Low or no hydraulic oil.

Fill hydraulic reservoir to correct level.

Faulty hydraulic pump.

See Troubleshooting of Hydraulic Systems in this section or see your John Deere dealer.

Lack of or restricted load sense signal due to plugged suction strainer in reservoir.

Inspect and clean strainer.

Faulty tread adjust valve.

See your John Deere dealer.

Load sense jamming valve not working.

See your John Deere dealer.

NXH8,M68440,L7 -19-07JUL98-1/2


Symptom Problem Solution

One individual tread adjust does not function, but others do.

Tread adjust shim pads gap adjustment incorrectly set.

Set tread adjust shim pads gap adjustment correctly. (See Chassis section in this manual.)

Check valve in load sense line stuck shut.

Clean, repair or replace check valve.

Plugged orifice in hydraulic line.

Replace orifice.

Faulty solenoid valve.

Switch coil with good coil, if function operates, replace coil.

Damaged electrical harness.

Repair harness.

Broken, damaged or worn shim pads.

See your John Deere dealer.

Damaged or corroded electrical connection.

Repair, replace or clean electrical connection.

Faulty tread adjust cylinder.

See your John Deere dealer.

Faulty tread adjust diode.

Replace diode.

Faulty tread adjust valve.

See your John Deere dealer.

One individual tread adjust does not stop when switch is released.

Faulty solenoid valve.

Repair or replace solenoid valve.

Sticking or faulty switch.

Replace switch.

Sticking hydraulic spool.

Clean repair or replace.

Excessive front tire wear or poor row tracking.

Improper toe-angle adjustment.

Adjust toe angle.

NXH8,M68440,L7 -19-07JUL98-2/2