throw out of gear
throw out of gear {v. phr.}
1. To separate the gears of (a car or some other machine) when you want to stop it.
When John wanted to stop, he threw the car out of gear and braked sharply.
2. To stop or bother (what someone is doing or planning); confuse; upset.
The whole country was thrown out of gear by the assassination of the President.
My mother's illness threw my plans for the summer out of gear.
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Source: A Dictionary of American Idioms