Testing and Adjusting
Machine Preparation for
SMCS Code: 3203-735; 4351-735
Refer to the following warnings for all inspections and tests of
the propel system. If the source of the problem is not
determined, perform the inspections and tests. Perform the
inspections and tests in sequential order. For all tests, the oil
in the propel system must be at normal operating temperature.
Sudden movement of the machine or release of oil under
pressure can cause injury to persons on or near the
To prevent possible injury, perform the procedure that
follows before testing and adjusting the power train.
Personal injury can result from hydraulic oil pressure and
Hydraulic oil pressure can remain in the hydraulic system
after the engine has been stopped. Serious injury can be
caused if this pressure is not released before any service
is done on the hydraulic system.
Make sure all of the attachments have been lowered, oil is
cool before removing any components or lines. Remove
the oil filler cap only when the engine is stopped, and the
filler cap is cool enough to touch with your bare hand.
Care must be taken to ensure that fluids are contained
during performance of inspection, maintenance, testing,
adjusting and repair of the machine. Be prepared to
collect the fluid with suitable containers before opening
any compartment or disassembling any component
Refer to Special Publication, NENG2500, "Caterpillar Tools
and Shop Products Guide", for tools and supplies suitable
to collect and contain fluids in Caterpillar machines.
Dispose of all fluids according to local regulations and
Release the pressure in the hydraulic system (page
During a diagnosis of the hydraulic system, remember that
correct oil flow and pressure are necessary for correct
operation. The output of the pump (oil flow) increases with an
increase in engine speed (rpm) and decreases when engine
speed (rpm) is decreased. Oil pressure is caused by
resistance to the flow of oil.
Before any tests are made, visually inspect the complete
hydraulic system for leakage of oil and for parts that are
damaged. For some of the tests, a magnet and a measuring
rule are usable tools.
When any test is made of the propel system, the hydraulic oil
must be at the normal temperature for operation.
Troubleshooting can be complex. A list of some of the
possible problems and corrections are on the following pages.