Just wanted some thoughts on an issue I have with a two and a half year old MX5 which is still under Mazda's warranty. A few months ago I noticed a growling noise on idle just after start up from cold and when the revs had got back down to 1000 and under. This disappeared when the clutch was depressed but reappeared when the clutch was released. It also disappeared after the car was warmed up. I suspected a noisy gearbox bearing, possibly the main shaft which I think stops turning when the clutch is depressed. The Mazda dealer eventually agreed there was a noise but said it was nothing to worry about and Mazda wouldn't dismantle to investigate anyway! I've never heard such a noise on any manual car I've had, some with very high mileages, so I don't know if this is unique to this car. I certainly don't recall hearing it when the car was bought from new.

The noise has got louder and I'm even more concerned there is a problem with a bearing, which if is the case I want sorted out in warranty. To try and alleviate any fight with the dealer I'm thinking of taking it to a gearbox specialist first to confirm that what I'm hearing is an issue. If they confirm I can take it back to Mazda with some sort of backup. Any views on whether this is a good approach, or should I take it straight back to Mazda? Luckily not having to claim under warranty before in the past, if the dealer disagrees there is a problem what recourse do I have in these situations?