GEAR 8D6491 - Caterpillar

Note: Fuel consumption in this Operation and Maintenance Manual, "Maintenance Interval Schedule" is based on a load factor of approximately 40 percent.Refer to this Operation and Maintenance Manual in order to determine the maintenance interval for a major overhaul.The need for a major overhaul is determined by several factors.
An increase of oil consumption
An increase of crankcase blowby
The total amount of fuel consumption
The service hours of the engine
The wear metal analysis of the lube oil
An increase in the levels of noise and vibrationAn increase of wear metals in the lube oil indicates that the bearings and the surfaces that wear may need to be serviced. An increase in the levels of noise and vibration indicates that rotating parts require service.Note: It is possible for oil analysis to indicate a decrease of wear metals in the lube oil. The cylinder liners may be worn so that polishing of the bore occurs. Also, the increased use of lube oil will dilute the wear metals.Monitor the engine as the engine accumulates service hours. Consult your Caterpillar dealer about scheduling a major overhaul.Note: The driven equipment may also require service when the engine is overhauled. Refer to the literature that is provided by the OEM of the driven equipment.A major overhaul includes all of the work that is done for the top end overhaul and the general inspection. A major overhaul includes additional parts and labor. Additional parts and labor are required in order to completely rebuild the engine.For the major overhaul, all of the bearings, seals, gaskets, and components that wear are disassembled. The parts are cleaned and inspected. If necessary, the parts are replaced. The crankshaft is measured for wear. The crankshaft may require regrinding. Alternatively, the crankshaft may be replaced with a Caterpillar replacement part.Your Caterpillar dealer can provide these services and components. Your Caterpillar dealer can ensure that the components are operating within the appropriate specifications.If you elect to perform an overhaul without the services of a Caterpillar dealer, be aware of the following recommendations.Replacement of Components
Replace the following components during the major overhaul.
Connecting rod bearings
Crankshaft seals
Crankshaft vibration damper
Electronic fuel injectors
Main bearings
Piston rings
Nonmetallic fuel lines (if equipped)Inspection, Reconditioning or Exchanging of Components
Inspect the following components according to the instructions that are in Caterpillar reusability publications. Refer to Guidelines for Reusable Parts and Salvage Operations, SEBF8029, "Index of Publications on Reusability or Salvage of Used Parts".Recondition the worn components or exchange the components, if necessary. Your Caterpillar dealer can provide these services and components.
Camshaft followers
Connecting rods
Cylinder head assembly
Cylinder liners
Engine wiring harness
Exhaust bellows
Fuel transfer pump
Oil pump
Pistons
Piston pins
Prelube pump
Spacer plate
TurbochargersInspection of Components
Inspect the following components according to the instructions that are in Caterpillar reusability publications. Refer to Guidelines for Reusable Parts and Salvage Operations, SEBF8029, "Index of Publications on Reusability or Salvage of Used Parts".
Camshaft
Camshaft bearings
Crankshaft
Crankshaft thrust washers
Driven equipment (alignment)
Engine control module
Front gear train
Gear train bushings and bearings
Rear gear trainInspect the camshaft for damage to the journals and the lobes. Inspect the following components for signs of wear and/or for signs of