- Wheel Loader:
- 994 (S/N: 9YF1-UP)
- 994D (S/N: 3TZ1-UP)
Several improvements have been made to the freewheel stator in the torque converters for the 994 Wheel Loaders and the 994D Wheel Loaders. Refer to Table 1 for a list of the former part numbers and the new part numbers. Two reusability guidelines have been published in order to help the reader identify the reusable parts in the freewheel stator. These guides also demonstrate the differences in the freewheel stator between the off highway trucks and the loaders. In addition to the improved parts, new software is available. The new software will reduce the torque spikes during directional shifts. In order to help maximize the life of the clutch in the freewheel stator, a list of helpful operating techniques has been included at the bottom of this article.
A new 266-3688 Flash file is available only for the 994D Wheel Loader. The flash file provides Control Throttle Shifting (CTS) for directional shifts. The new flash file enables CTS only during directional shifts. CTS lowers the engine speed briefly during a directional shift. Testing during a typical cycle of truck loading has shown cycle times to increase by less than 1 second.
Two reusability guidelines have been created in order to help make decisions during repairs. The Special Instruction, SEBF8996, "Reusability Guideline for a 994 and 994D Wheel Loader Freewheel Stator" refers to the 994 Wheel Loaders and the 994D Wheel Loaders. The Special Instruction, SEBF8997, "Reusability Guideline for a 789, 789B, 789C, 793, 793B and 793C Off Highway Truck Freewheel Stator" refers to the off highway trucks. These two documents describe the differences in the applications and the different criteria for the reusability of the parts. By following the guidelines, the life of the freewheel stator will be maximized and the unscheduled down time due to failures of the freewheel stator will be minimized.
Operating techniques have a large impact on the life of the freewheel stator. Use the following 3 suggestions in order to maximize the life of the freewheel stator.
- Limit the number of nonmodulated, high idle directional shifts. This can be accomplished automatically by flashing the new software that is listed above. This can also be accomplished by releasing pressure on the throttle pedal or by using the left pedal.
- Do not pump the left pedal when you are digging. This is especially true on 994 Wheel Loaders that have not been retrofitted with the STIC update. This will cause cycles of high stress as well as additional damage that results from engaging and disengaging the clutch rapidly.
- Do not load the bucket when the lockup clutch is on. This is only applicable for the 994 Wheel Loaders without the STIC update.
| Improved Parts | ||
| Former Part Number | Part Description | New Part Number |
| 7T-1332 | Freewheel Cam | 259-6986 (1) |
| 7T-1664 | Roller Cage | 259-7002 (1) |
| 111-4208 | Split Washer | 259-7001 (1) |
| ( 1 ) | These parts can be used on the off highway trucks, but the parts are intended for the more demanding 994 applications. |