Usage:
NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
NOTE: This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS8656" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
Termination Date
October 31, 1996Problem
The 7X3348 Bolt that mounts the 7E3755 Oil Pump Idler Gear to the Oil Pump in the Front Gear Group of 3114 Engines with serial number prefix 4RR used in certain IT24F Tool Carriers, 924F Wheel Loaders, and 446B Backhoe Loaders may not have been tightened properly. If the bolt was tightened improperly there is a possibility that within the first 400 hours of operation the bolt will loosen and the idler gear will misalign with other mating gears and result in damage to the front gear train.
Affected Product
Model & Identification Number
(Only Product with Engine Serial Number Prefix of 4RR)
446B (5BL828-855, 5BL858-867, 5BL869-947, 5BL949)
IT24F (4NN369-389, 4NN391-428, 4NN443-465, 4NN467-475, 4NN477-485)
924F (5NN472-481, 5NN483-499, 5NN511-531, 5NN533-569, 5NN571-579, 5NN587-589 )
Parts Needed
- 1 - 3J7354 Seal (924F and IT24F Only)
- 1 - 7W5340 Gasket
- 1 - 7X3348 Bolt (Required only if inspection reveals bolt was improperly tightened)
- 1 - 1193072 Oil Pan Gasket
- 1 - 7W5340 Gasket
Action Required
If a machine has operated less than 400 hours it is recommended to remove the engine oil pan and verify that the oil pump idler bolt has not loosened. If a machine has operated for more than 400 hours the possibility that the bolt was not tightened properly is very small. See attached rework procedure.
Service Claim Allowances
NOTE: IT24F and 924F Models may claim an additional 2.0 hours, due to the difficulty in removing the oil pan.
An additional 0.5 hours may be claimed if the oil pump idler bolt is found loose and must be replaced.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach.
- (1-Rework Procedure)
Rework Procedure
Inspection Procedure
Idler Gear Bolt Torque
NOTE: In addition to the parts listed, the serviceman will need the following items: 9 liters (9.5 quarts) engine oil, 10 liters (10.5 quarts) engine oil if the oil filter is changed at the request of the owner and 1U8846 Sealant for use when the oil pan is installed.
1. To access the oil pan, remove the transmission and engine crankcase guard (Belly Guard) if equipped. On the 924F or IT24F it will also be necessary to disconnect the rear wheels and axle and raise the frame to access the oil pan. The procedure to remove the wheels and axles are as follows:
a) Jack up the vehicle and place the rear of the vehicle on machine stands.
b) Turn off main disconnect switch.
c) Open Hydraulic tank cap to relieve pressure. Operate the brakes to bleed down the brake accumulators.
d) Remove driveshaft connecting transmission to rear axle input yoke.
e) Disconnect brake line at axle. Cap off lines to minimize oil loss.
f) Disconnect remote grease lines to front and rear trunnion.
g) Loosen and remove 24 bolts used to fasten the axle trunnions to the frame and raise the frame high enough off of the axle using the jacks to remove the oil pan.
h) Assemble in reverse order. Replacing the 3J7354 Brake Line Seal when connecting brake line to the axle is recommended.
2. Remove the oil pan. Refer to the Basic Engine Components Disassembly and Assembly Service Manual for 3114, 3116 and 3126 Engines, Form Number SENR3611 for details on oil pan removal and installation.
3. Remove the Oil Pump Suction Tube Assembly.
4. Check the torque on the Oil Pump Idler Gear Bolt (1). The torque for this bolt is 70 ± 15 N·m (50 ± 11 lb ft) and can be checked without removing the oil pump. If the torque on the bolt is within the specified limits proceed to Step 8 and assemble the engine as no further inspection or repair is required. If the torque of the bolt is below the specified limit, proceed to Step 5 for further inspection and repair.
Illustration 1
5. Inspect the Oil Pump Gear, Oil Pump Idler Gear, and other mating gears for chipped or damaged gear teeth. If damage is evident, repair as needed. A separate claim must be submitted for repairs other than the inspection and bolt replacement. If the gears are not damaged proceed to Step 6.
6. Loosen the idler gear bolt (1) until it is possible to rotate the idler shaft (2) with the shaft mounted to the oil pump. The shaft can be rotated by using the 6V0006 Soft Nose Governor Linkage Tube Pliers from the 3100 MUI Fuel System and Valve Setting Tool Group, Part No. 1288822, or other soft jawed pliers.
NOTE: Using pliers without cushions could damage the idler shaft and gear.
Rotate the shaft clockwise until it stops, noting the shaft position, then rotate the shaft Counterclockwise till it stops noting where the shaft is positioned. Center the shaft between the two stops (this centers the mounting bolt location in the oil pump body assembly which eliminates the possibility of bolt side loading due to shaft misalignment) and hold in position while removing the 7X3348 Bolt for replacement. Replacement is required as the bolt is treated with a locktite material, which may have lost its locking capability, plus the bolt threads may have been damaged as a result of the threads being side loaded against the oil pump body when the bolt was initially installed.
7. Use the soft nose pliers and hold the idler shaft in the center position noted in step 6. and install a new bolt. As the bolt is tightened it will pull the shaft up against the oil pump body so that the bolt can be tightened to the specified torque of 70 ± 15 N· (50 ± 11 lb ft). While tightening the bolt, observe the idler shaft to insure that it stays in its centered position.
NOTE: If the shaft moves it is possible that the bolt threads will come in contact with the oil pump body side loading the threads and resulting in a false torque.
8. Insure that the gasket surface is clean and install the Oil Pump Suction Tube Assembly using a new 7W5340 Gasket. Tighten the tube assembly bolts to a torque of 28 ± 7 N· (20 · 5 lb ft).
9. Insure that the gasket surfaces of the oil pan and block are clean and install the engine oil pan. The engine oil pan gasket part number is 1193072. Refer to the Basic Engine Components Disassembly And Assembly Service Manual for 3114, 3116 and 3126 Engines, Form Number SENR3611 for installation instructions. Follow the procedure for gasket installation closely as failure to do so could result in oil leaks after the oil pan is installed.
10. Install axle, axle trunnions, brake line, grease line, and driveshaft. See Step 1 for details and install crankcase guard (Belly Guard) if equipped. Check and replace fluids as needed.