Just today my car (Y reg Kia Shuma) has started behaving rather oddly. When the engine is cold it behaves just fine, but once the engine is warm, it really doesn't like being below about 2500 RPM. If that happens, the gearbox makes 'chr-rrrr-rrrr' noises. This makes driving smoothly and slowly very difficult.
I think it's the gearbox because if I put the car in neutral, the noises disappear. My car didn't used to do this. It's done less than 30K miles. It normally does 30 miles a week, with the odd 100-mile trip. What's happenned?