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Q: Why is my 4-wheel drive engaging while I'm driving?

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As I start to drive, not even reaching 10mph, I've gone about 4-6ft and my 4 wheel drive engages. I stop, put it in neutral, put it back to auto and after about 4-6ft more, it engages back into 4 wheel drive. What could be happening?

My car has 125000 miles.
My car has an automatic transmission.

A: Hey there. Driving with 4x4 on when it is n...

Hey there. Driving with 4x4 on when it is not needed can be rough on the axles, transmission, and hubs. The 4x4 engaging on its own can be the result of a mechanical error or an electrical error.

Mechanically if there is a vacuum leak in the system that engages the 4x4, the hubs can engage automatically if the wheels are rolling. There are other standards that need to be met for this to happen, which is why it is happening under certain conditions. There are a set of vacuum lines that run next to the battery that may need to be replaced.

There are several electrical components that have an effect on the system as well. Any issues like that would likely show on a diagnostic code scan.

If you would like to have this resolved, a certified technician from YourMechanic can come to your car's location to inspect the transmission and advice you any corrections needed.

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