Most stock Proton Wiras come equipped with the Mitsubishi-designed F5M series manual transmissions or the F4A series automatics. Identifying the code on the transmission housing tells you exactly what gear ratios and final drives you are working with.
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The phrase has also taken on a life in local mechanic slang: "Boss, kena code gearbox" means "trouble is coming, and it won’t be cheap."
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