FOAM 2704836 - Caterpillar

Probable Causes
Batteries
Components in the starting circuit
Flywheel ring gear
Transmission
PTO
Engine accessory
Hydraulic cylinder lock
Internal engine problemRecommended Actions
Check the Batteries
Check the charge on the vehicle's batteries. Charge the batteries, if necessary. Refer to Special Instruction, SEHS7633, "Battery Test Procedure".Load test the batteries. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries".Check the Starting Circuit
Check the wiring to the starting motor solenoid. Refer to the vehicle's electrical schematic.
Check the engine start switch and the engine start relay for electrical power.
Check the starting motor cables. If the starting motor cables are corroded, remove the starting motor cables and clean the starting motor cables.
Test the operation of the starting motor. Check the Flywheel Ring Gear
Inspect the flywheel ring gear for damage.Check the Transmission
Verify that the driveline moves freely.Check the PTO
Ensure that the PTO system is operating correctly.Check the Engine Accessories
Remove engine accessories that may lock up the engine and inspect the accessories.The following accessories may lock up the engine:
Air compressor
Power steering pump
Engine oil pumpCheck for Hydraulic Cylinder Lock
Check for fluid in the cylinders (hydraulic cylinder lock) by removing the individual electronic unit injectors.Note: Fuel will flow from the cylinder head into the cylinders when a electronic unit injector is removed.Check for an Internal Engine Problem
Disassemble the engine. Refer to the engine's Disassembly and Assembly manual. Inspect the internal components for the following conditions:
Seizure
Broken components
Bent components