| 摘要 |
A vehicle mechanical transmission includes a conventional shift lever which enables the vehicle driver to manually select lower gear ratios, and an automatic shifting mechanism which provides automatic shifting between selected higher ratios once the driver has moved the shift lever to an "automatic" position. The transmission includes a plurality of shift rails which are individually and selectively moveable from a neutral position to two different gear positions. In accordance with the present invention, the shift lever is only coupled to mechanically shift a portion of the shift rails, typically those shift rails corresponding to the lower gear ratios. Once all the lower ratios have been selected, the driver can move the shift lever to an "automatic" position. When in this position, the shift lever actuates an electronic control, which in turn automatically controls the shifting of at least one shift rail in accordance with the status of various monitored vehicle operating parameters. In addition to a conventional interlock between each of the shift rails, an auxiliary interlock system is provided to prevent the shift lever from being moved to the automatic position simultaneously with the shifting of a manually actuated shift rail. Further, the transmission includes a driver actuated manual override valve to cause the automatically shifted rail to return to its neutral position in the event of failure of the automatic shifting mechanism.
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