Starting Vehicles: Gears Engaged or Not?

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Discussion Overview

The discussion revolves around the ability to start vehicles with the gears engaged, exploring the differences between manual and automatic transmissions and the conditions under which this is possible. It includes considerations of mechanical systems and ignition types.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • Some participants suggest that certain vehicles can be started with the gears engaged, while others cannot, indicating a distinction based on vehicle type.
  • One participant mentions the concept of a "push start," which typically applies to manual transmissions, where the vehicle is pushed to get it rolling before engaging the gears.
  • It is noted that automatic transmissions may not allow for push starting due to the dependency on a pump driven by the engine, which does not engage if the engine is not running.
  • A participant points out that vehicles with electronic ignition systems may also fail to start if the battery is dead, as insufficient power would prevent the system from functioning during a push start.
  • Another participant shares a personal experience with a manual transmission vehicle, stating that they have successfully started an unresponsive car by engaging the lowest gear and using the ignition and starter motor.
  • Discussion includes mention of specific features in older GM automatic transmissions, such as "grade retard" and rear pumps, which may influence starting behavior.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the ability to start vehicles with gears engaged, as differing views on the mechanics of manual versus automatic transmissions and specific vehicle features are presented.

Contextual Notes

Limitations include the lack of detailed specifications on vehicle types and conditions under which starting with gears engaged may or may not work, as well as the dependence on the state of the battery and ignition system.

akhand121
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certain vehicles can be started by keeping the gears engaged while certain others cannot...how ?
 
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Specify which types of vehicle can be started with gears engaged.
 
akhand121 said:
certain vehicles can be started by keeping the gears engaged while certain others cannot...how ?

Are you referring to what is known as a "push start"? This is where you push the car to get it rolling and then engage the gears to crank the engine.

If so, this generally only works if you have a manual transmission. Automatic transmissions usually have a pump that is run off the engine. If the engine isn't already running, the transmission won't engage the gears and the car effectively stays in neutral.

Another reason that you might not be able to push start a car is if it has a electronic ignition system. If the battery is completely or nearly complete dead, it won't have enough juice to run the system and at the low speed the engine turns during a push start, the alternator won't either.
 
On automatic transmissions, you will have to have a "rear pump" driven by the output shaft.

Some GM transmission of the early 60s had what is called "grade retard" which was found in the dynaflow and turboglide.

Some versions had a rear pump.
 
I have a manual transmission. I have been able to move the unresponsive car by engaging lowest gear and operating the ignition and starter motor. Sometimes it then jumps to life, and one can carry on as if nothing had happened!
 

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