Can You Put Your Automatic Transmission Car in Reverse on the Highway?

Have you ever wondered what would happen if you put your automatic transmission car in reverse while driving on the highway at 110 km/h? This article explores the potential consequences and explains why attempting such an action is ill-advised.

The History of Accidental Reversing

When I was a kid, I accidentally put my Datsun truck, which had a Borg-Warner 3-speed automatic transmission, into reverse while traveling at a high speed. The force of the event resulted in a cracked transmission case, necessitating the replacement of the entire unit. I saw this as an opportunity to upgrade to a four-speed manual transmission.

Modern Electronic Controls

However, with modern electronically-controlled cars, it is practically impossible to achieve such a feat. The car's computer system detects the error and prevents the transmission from engaging in reverse at high speeds. The transmission would likely ignore the input until the vehicle comes to a stop.

The Impossible Scenario

Even if hypothetically you were to put the gearshift into reverse, the actual gear would not be able to engage at such high speeds. This is due to the synchronizer being thrown off, which would lead to a significant jerk and rattling noise. It is highly likely that parts of the transmission would be damaged, potentially resulting in a total failure.

R gears might become unavailable, including several forward gears, depending on the type of automatic transmission you have. Safety systems might also detect an issue, causing the car to stop functioning completely.

Common Protocols for Modern Vehicles

Most modern cars have safety protocols that lock out the reverse gear if the vehicle is moving at more than 5 miles per hour. These systems ensure that the gears will not engage until the vehicle has slowed down sufficiently. In cases where the transmission or the transmission control module is old or malfunctioning, a catastrophic failure could occur, causing damage to the transmission and potentially ejecting parts from the case.

Case Study: No Immediate Damage

Interestingly, not all cars react in the same way to attempts to engage reverse at high speeds. In one instance, I was driving a 2000 Toyota 4Runner with approximately 240,000 miles on it, and it is still in good condition. During a high-speed coast, I accidentally shifted into reverse and noticed the car did not react in any visible way. No noise, no discomfort, and the car's performance remained unchanged.

While the car did not experience immediate damage, it is crucial to remember that modern vehicles have sophisticated safety systems that prevent such actions. Attempting to engage reverse at high speeds could result in severe damage to the transmission, mechanical failure, and even total loss of control of the vehicle.

Conclusion

It is best to avoid putting your automatic transmission car in reverse while driving at high speeds. Modern vehicles have numerous safety measures in place to prevent this, and any attempt to engage reverse at high speeds could result in catastrophic failure. It is always advisable to follow the manufacturer's guidelines and adhere to safe driving practices.