1999 volvo v70 2.4 manual gearbox noise

[hello170879]

I have just purchased a v70 with a suspected crankshaft pulley problem, on further inspection, i have now pinpointed the noise to the gearbox area. The noise is only heard at idle and very low revs, clunking, like something is loose in the gearbox. All the gears are fine and engage perfectly, car drives great but this clunking noise persists when idling. we suspected flywheel or clutch was loose but now we are certain the noise is from inside the gearbox, possible differential. even thought pinions in the diff may be loose.
Anybody had any experience of such a problem???