JLG sky trak mmv Service Manual page 250

Transmission: ZF 4 WG-98 TS
7.9.1 Transmission Troubleshooting (Continued)
Problem
3. Low clutch pressure.
4. Lack of power.
5. Transmission overheating
(oil above 248° F [120° C]).
7.20
Cause
1. Incorrect oil level.
2. Main pressure valve stuck open.
3. Broken or worn coupling shaft or
piston o-rings.
4. Pressure reducing valve stuck
open.
1. Park or service brake dragging.
2. Low engine rpm causes
converter stall.
2. Pump output pressure is low.
3. Clutch discs worn or damaged.
4. Transmission overheating.
1. Low oil level.
2. Clogged radiator.
3. Transmission filled with incorrect
oil, or oil contaminated.
4. Excessive "roading."
5. Restriction in oil cooler hoses.
6. Pump worn or damaged.
7. Engine thermostat stuck.
Remedy
1. Fill transmission to correct level
with recommended oil (refer to
Section 2.13.10, a.
Transmission Oil Level Check ).
2. Clean the valve spool and
housing.
3. Replace coupling and/or o-rings.
4. Clean the valve spool and
housing.
1. Refer to Section 9.8, Hydraulic
Circuits and Troubleshooting .
2. Adjust the engine rpm to
specifications (refer to Cummins
4BTA 3.9 Service Manual).
2. Refer to Section 7.9.1,
Transmission Troubleshooting,
Step 2, Low or no pump flow or
pressure.
3. Replace clutch discs.
4. Refer to Section 7.9.1,
Transmission Troubleshooting,
Step 5, Transmission overheating
(oil above 248° F [120° C]).
1. Fill transmission to correct level
with recommended oil (refer to
Section 2.13.10, a.
Transmission Oil Level Check ).
2. Remove debris from the
radiator.
3. Drain transmission and fill to
correct level with recommended
oil (refer to Section 2.13.10, b.
Transmission Oil and Filter
Change ).
4. Stop and idle the engine.
5. Replace cooler hoses.
6. Repair or replace pump
assembly.
7. Replace engine thermostat
(refer to Section 8.6.2,
Thermostat Replacement ).
Model MMV Rev. 12/04