When the battery in an automatic transmission dies, the car cannot be started. This is because the starter motor will not engage without battery power and If you’re among the many people who think that pushing a button is easier and more fun than turning a key, you may be wondering how to push start an automatic transmission.
If your car has an automatic transmission, you cannot push start it. Some people believe that you can push start an automatic car by putting it in neutral and pushing it until it starts, but this will not work. The only way to start an automatic car is by using the key or the remote starter.
Before I continue further, the question arises can you push start an automatic car. If your car has an automatic transmission, you cannot push start it. Some people may try to tell you that it is possible, but it is not. You could damage your car by doing this and your car won’t start. Read more to know why it is not possible to push start an automatic car.
How To Bump/Push Start An Automatic Car
Push starting a car is a method of starting a car without using the battery. This can be done by using a second car to push the first car, or by using a rope to pull the car. When a car is pushed started, the engine is started by using a pushing force instead of a cranking force. This is done by having the car in neutral and then pushing the car until it reaches a speed of around 5-7 mph.
If you’re wondering whether you can push start an automatic car, the answer is no – it’s not possible. Here’s a look at why that is and what you can do if your car won’t start.
Automatic cars have a device called a torque converter that couples the engine to the transmission. This means that there is no direct connection between the engine and the wheels, so pushing the car won’t get it moving. In an older automatic transmission car, the bump/push start was possible, but in newer vehicles, it is impossible to push start the automatic car.
Older automatic transmission vehicles used some mechanism to push/bump start the car. That mechanism is used to create hydraulic pressure by pushing the car. The old automatic transmission cars had an additional oil pump driven by the transmission output shaft.
So, when the wheel was rotating while pushing, that forces the oil pump to create the hydraulic pressure in the gearbox, which was responsible for engaging and shifting the gear.
So, on older transmissions, the bump/push start of the automatic car was possible, but with a high pushing speed of almost 20-30 mph, which cannot be achieved with walking or running speed (need faster speed than you can push).
Now, come to the question of how to push start an automatic car. If you still have an older automatic transmission car and you want to push-start it. You should tow it to another car or let the car go downhill to have some motion of almost 20-30 mph. At this stage slowly put the shifter in the “D” drive position to start it.
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Push/Bump start suits manual transmission cars, not on an automatic transmission.
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Bump start does not effectively work with cars equipped with automatic transmissions. It is because the fluid pressure is not present in the automatic transmission gearbox while the bump starting.
It is because the automatic transmission has fluid clutches that require high pressure to engage the car into gears. And it cannot be achieved by slowly pushing the car which is why the car needs high-speed pushing.
But, in newer vehicles, this hydraulic pump is removed due to a change in design, which made it impossible to push/bump start a modern automatic transmission.
The Secret Behind Why An Automatic Transmission Car Does Not Bump/Push-Start
Manual and automatic cars have different types of transmission. In a manual transmission, it is easy to put the car into gears while the wheels are moving. It is because the manual transmission has a clutch that directly connects and disconnects the engine to the transmission.
When you foot off the clutch pedal, while the wheels are moving in a push-starting manual car, the engine and transmission physically connect, which causes the transmission to move the engine with itself.
But in an automatic transmission, the car cannot go into gears while push-starting (The purpose of putting the transmission into gears while pushing, is to spin the engine to start). In an automatic transmission, the traditional clutch is replaced with a torque converter.
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Remember, the essence of pushing the car is to create motion in transmission while putting the car into gear, this motioned gear then spins the engine and starts it. If the car refuses to go into gears (like automatic transmission) while having motion, then your engine will not spin as a result, your car will not start.
The torque converter is a hydraulic-operated device that transfers the movement from the engine to the transmission. The automatic transmission uses hydraulic pressure to engage and disengage the gears. This hydraulic pressure is created by the hydraulic pump, which is driven by the torque converter. And the torque converter is spun by the engine.
When the engine is turning, the torque converter and hydraulic pump also turn, which produces the hydraulic pressure. This hydraulic pressure goes into the valve body to the clutch plates of the automatic transmission for a specific gear change.
The pressurized hydraulics flow shifts the gears and lubricates the internal parts of the automatic transmission. When there is no engine turning, there will be no torque converter spinning and pump pressure. So, when there is no pressure, there will be no engagement of gears.
With the Off engine, the automatic transmission does not have hydraulic pressure. When you push the automatic car, chances are you would not turn the torque converter, which would not turn the pump, and the hydraulic pressure will not be produced. So, there would be no gear engagement or gear change in the gearbox. Hence, the automatic car engine would not spin and start.
Here is what I mean when there is no gear engagement while bump-starting, there will be no engine turning. Because this revolving transmission forces the engine to spin, which results in starting the car. So, bump-starting the modern automatic transmission car will bring damage to your car’s transmission. You should call for roadside assistance or for a towing service to tow the car with another car or jump-start it.
Here’s The Engineer Adam Cole, who works for a major automaker, wrote on Jalopnik.
So, in order for a gear to become engaged, line pressure must first be built up but you cannot increase line pressure by spinning the output shaft of the transmission. You would also have to produce enough torque in order to spin the torque converter fast enough to restart the engine. However, no clutches would be engaged, therefore the torque generated by the spinning wheels will never make it to the torque converter which ultimately results in the inability to bump-start the vehicle.Adam Cole
Final Thought About Push Start Automatic Car
Automatic transmission is operated on hydraulic pressure. It requires an engine turning for the pump to create the hydraulic pressure to put the transmission into gear. Conversely, in bump-starting the automatic transmission car, the wheels will not turn over the torque converter, which will not activate the hydraulic pump.
As a result, the fluid pressure will not build up and the car will refuse to go into gears. And when the car does not go into gears, how would you spin the engine to start. I mean, if the automatic car does not go into gears, then the engine will not spin and start while bumping/push-starting.
No, you cannot push start an automatic car. Automatic cars have a device called a torque converter that couples the engine to the transmission. This device contains a fluid that transmits power from the engine to the transmission. When the car is not running, there is no fluid movement and therefore the car cannot be pushed started.