- Off-Highway Truck/Tractor:
- 784B (S/N: 5RK)
- Wheel Loader:
- 994 (S/N: 9YF)
- 784C (S/N: 2PZ)
- 785B (S/N: 6HK)
- 785C (S/N: 1HW; APX; 5AZ)
- 789B (S/N: 7EK)
- 789C (S/N: 2BW)
- 793B (S/N: 1HL)
- 793C (S/N: 4AR; ATY; 4GZ)
- 994D (S/N: 3TZ)
Several changes have been made to the Rockford 270 fan clutch that is on the large off-highway trucks and wheel loaders. This article will explain those changes.
The original 100-8105 Fan Drive Gp was manufactured from 1993 to 1996. This clutch experienced the following issues: rotating bearings, leaking seals and short life of the fan drive belt.
The 129-9494 Fan Drive Gp was introduced in 1996. This fan clutch includes a speed sensor in order to improve fan speed control through the ECM. The ECM controlled fan clutch provides an easier modulation than the analog controlled fan clutch. The ECM also allows a slower engagement of the fan. The slower engagement prolongs the life of the fan drive belts. This clutch experienced the following issues: rotating bearings and leaking seals.
Reference: See Service Magazine, SEPD0346, 24 February 1997, "New ECM Controlled Variable Speed Fan Clutch Group Available".
Reference: See Special Instruction, REHS0023, "ECM Controlled Variable Speed Fan Clutch Group For 785B, 789B, and 793B Off-Highway Trucks".
The 133-5969 Fan Drive Gp was produced from 1996 to 1999. The 133-5969 Fan Drive Gp had an improved design of the rear main bearing on the fan clutch. This bearing was designed to prevent the bearing from rotating, which can lead to a leaking seal. Rotation can allow movement of the shaft, which causes excess wear to the seal. This clutch experienced the following issues: rotating bearings and leaking seals.
Reference: See Service Magazine, SEPD0403, 9 February 1998, "New Fan Drive Group (Variable Speed) Provides Increased Service Life".
In 1998, the lube hole to the bearings was removed in order to reduce the amount of oil at the seal. This was done in order to reduce the occurrences of leaks.
The 163-2592 Fan Drive Gp was put into production in April 1999. This variable speed fan clutch incorporates a pinned bearing in order to prevent any rotation of the bearing. The correct tools must be used when the 163-2592 Fan Drive Gp is serviced. Failure to use the proper tooling can result in leaks and premature failure.
Reference: For the proper tooling, see Service Manual, RENR2634, "784C Tractor and 785C, 785C HAA, 789C, and 793C Off-Highway Truck Variable Speed Fan Drive".
Reference: See Service Magazine, SEPD0619, 04 March 2002, "Fabricated Tools Are Required For The Disassembly And Assembly Of The Variable Speed Fan Drive".
Do not use the tools that are called for in Service Manual, SENR8603, "Variable Speed Fan Clutch" and Service Magazine, SEPD0410, 30 March 1998, "Use FT2461 Pressing Bar, FT2462 Pressing Tube, FT2463 Ring, FT2464 Plate, FT2465 Plate, FT2466 Mounting Plate, And FT2467 Rotating Plate To Disassemble And Assemble Variable Speed Fan Clutch". The tools that are called for in these publications can cause leaks and premature failures if these tools are used to service the 163-2592 Fan Drive Gp .
Reference: See Service Magazine, SEPD0503, 3 January 2000, "New Fan Drive Group Includes Serviceable Magnet And Pinned Bearing Races".
The 163-2592 Fan Drive Gp and the 0R-1039 Fan Drive Gp are manufactured or remanufactured with all the latest modifications and updates. The service life of these clutches should extend to the engine overhaul. In order to obtain the full service life of the clutch, Caterpillar recommends using a new 163-2592 Fan Drive Gp or a remanufactured 0R-1039 Fan Drive Gp when the following parts are serviced: the 100-8105 Fan Drive Gp, the 129-9494 Fan Drive Gp and the 133-5969 Fan Drive Gp.