How do you tell transmission is bad?

Signs of a bad transmission include unusual noises like grinding or clunking when shifting gears, slipping out of gear unexpectedly, and delayed or harsh shifting. You might also notice fluid leaks under the vehicle or a burning smell, which could indicate overheating. Additionally, warning lights on the dashboard, such as the check engine light, can signal transmission issues. If you experience any of these symptoms, it's advisable to have a professional mechanic inspect your vehicle.