For sometime I have had noises from the front of the car on overrun which could mainly be heard in first and second gear.

Having changed all fluids last week (which could just be coincidence) for a trip to Le Mans this weekend on overrun in every gear the noise is much louder and in every gear.

I thought that it was the gearbox and perhaps the synchro's so drove 600 miles over the weekend without any down changes and coasted up to junctions and used the brakes - quite ionteresting to say the least.

As well as the exhaust sooting up perhaps becasue of the coasting up to junctions, on the way back I tried several down changes to listen to the noises on the overrun.

Whilst my initial diagnosis was the gearbox/synchro's I am now thinking it sounds perhaps more metallic and perhaps heat shields but it is very difficult to actually determine.

Any suggestions and if it is the gearbox how long is it likely to last before it gives up ?.

 

could be clutch release bearing?
sounds like a tin can with a few beans in it being rattled on lift off, goes away when throttle derpressed again?

might not be though