- Off-Highway Truck/Tractor:
- 793F (S/N: SND1-UP; SSP1-UP; RBT1-UP)
- 797F (S/N: LAJ1-UP; WSP1-UP)
Description of Change:
Improvements (793F & 797F)
- Improvements to the Transmission Output Speed Sensor Software Strategy to reduce the occurrences of the Level 3 TOS Mismatch Events E330.
- Addition of a new diagnostic was added to detect if the Transmission Output Speed Sensors are wired backwards. CID 585-7 and CID 673-7, Level 1 Diagnostic, will be logged against both TOS sensors if the software detects that the sensors are swapped.
- The software determines that the sensors are swapped when the transmission is in a Forward Gear >1, and the sensed direction is reversed.
Improvements (797F)
- Improvements to the Fill Calibration Procedure to eliminate calibration failures for clutch 7.
- The addition of a Level 1 Event was added to the Transmission Internal Component Overspeed Event, EID 1293. A short overspeed will activate a level 1 event, and a longer overspeed will activate a Level 3.
- Improvements to the Lock Up Clutch Control Timing Strategy to reduce potential torque spikes in the drivetrain.
- Improvements to control directional shifts at higher engine RPM to reduce Train 1 failures.
Note: The Transmission S/N must be entered through Cat ET. The expected transmission S/N prefix should be "JH5" for a newer transmission, or "R1N" for an older transmission. A Transmission Fill Calibration and Engagement Calibration Procedure will need to be performed after installing this software.
Tests are now performed in the factory at the end of the production line. The test checks for the proper connections to the transmission output speed sensors. The tests verify that the harness connectors are wired correctly.
Adaptable To:
| Qty | New Part Number | Former Part Number | Description |
|---|---|---|---|
| 1 | 464-8205 | 454-9212 | Power Train Software Gp |
Note: Cat® ET (release 2014A v1.0 or later) service tool is required.
| Effectivity of the new 464-8205 Power Train Software Gp | ||
| Sales Model | Adaptable to Machines | Effective in Production with Machines |
| 793F | S/N:SSP1-977 | S/N:SSP978-UP |
| 793F CMD | S/N:RBT1-171 | S/N:RBT172-UP |
| 793F XQ | S/N:SND1-131 | S/N:SND132-UP |
| 797F | S/N:LAJ1-363 | S/N:LAJ364-UP |
| 797F XQ | S/N:WSP1-114 | S/N:WSP115-UP |
If necessary, use the following procedure to inspect the connections, and correct the faults on machines with power train software versions previous to 464-8205 Power Train Software Gp .
- Prepare machine for maintenance. Refer to the Operation and Maintenance Manual, "Prepare the Machine for Maintenance" for your machine.
- Ensure that the oil in the rear axle housing is not overfull and at the correct level. Adjust oil level if necessary. Refer to the Operation and Maintenance Manual, "Differential and Final Drive Oil Level - Check" for your machine.
- On 797F machines only, disconnect the transmission output speed sensor harness (1) on the differential access cover. Refer to Image 1.
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| Illustration 1 | g03731459 |
- Remove differential access cover (2) and retain the hardware. Note: Care must be taken to protect the differential against contamination with the cover removed.
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| Illustration 2 | g03731464 |
Differential access cover (2) for 797 machines | |
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| Illustration 3 | g03731476 |
Differential access cover (2) for 793F machines | |
- Inspect the harness connections to the transmission output speed sensors.
On 797F machines, transmission output speed sensor #1 (bottom sensor) (4) should be connected to the harness breakout that includes wires E901-GN and E900-WH. Transmission output speed sensor #2 (upper sensor) (3) should be connected to the harness breakout that includes wires E907-GY and E906-OR.
On 793F machines, transmission output speed sensor #1 (bottom sensor) (6) should be connected to the harness breakout that includes wires E900-YL and E901-GN. Transmission output speed sensor #2 (upper sensor) (5) should be connected to the harness breakout that includes wires E906-OR and E907-GY.
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| Illustration 4 | g03731481 |
797F machines, transmission output speed sensors | |
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| Illustration 5 | g03731496 |
793F machines, transmission output speed sensors | |
- After ensuring that the transmission output speed sensors are assembled correctly reinstall parts that were previously removed.