Automatic I would assume. Have you payed attention to the revs the engine is at when you do this? Are you selecting reverse within 10 seconds of a complete cold start? If so, wait about 20-30 seconds until the revs drop down to 1000RPM (or very close to) and then try selecting reverse. See if it does it much smoother then. So in other words, when you experience this issue, how high are your engine revs? Nah. No noise when selecting reverse gear. The noise appears before the 1st gear change only when I reverse the car first and drive forward.