Can anybody tell why when i start car up it is coldi can hear a grinding noise in or around the gear box but goes away warm you put clutch thanks?

There are a few possible reasons why you might hear a grinding noise in or around the gearbox when you start your car up cold, but the noise goes away once the car is warm and you put the clutch in.

1. Low transmission fluid level: If the transmission fluid level is low, it can cause the gears to grind when they are engaged. This is because the fluid helps to lubricate the gears and reduce friction. When the fluid level is low, there is less lubrication and the gears can grind against each other.

2. Worn transmission components: If the transmission components are worn, they can also cause a grinding noise. This is because the worn components can no longer mesh properly and they will grind against each other when they are engaged.

3. Damaged synchronizers: The synchronizers in a transmission are responsible for matching the speed of the gears before they are engaged. If the synchronizers are damaged, they can cause the gears to grind when they are engaged.

4. Input shaft bearing failure: The input shaft bearing is responsible for supporting the input shaft of the transmission. If the input shaft bearing fails, it can cause the input shaft to wobble and this can cause the gears to grind.

5. Bad clutch release bearing: The clutch release bearing is responsible for disengaging the clutch when the clutch pedal is depressed. If the clutch release bearing is bad, it can cause the clutch to drag and this can cause the gears to grind.