My gearbox whines badly in all gears but you hear it mostly in the higher gears.
Noise aside its a good gearbox and is very tight and precise in the selection. No baulking or grinding or jumping out of gear. Its just that whine on long motorway runs does my head in. Clutch kit is new and the fluid is at the correct level.

If I dip the clutch at speed the noise disappears then release it and the noise returns - I am told that this rules out any problems with worn diff bearings and it is more likely to need a set of new main shaft bearings which would cure the whines.

Can anyone shed any light on this problem and does this sound about right as diagnosis? Is swapping out bearings a DIY job or best left to just take the lump of useless metal to a gearbox specialist (that itself can be a whole world of hurt if I take it to a muppet who just steam cleans it then charges me £600)

Any pointers appreciated because gearboxes to me are just witchcraft

Just not sure a) how much a bearing set will cost me roughly and b) whether on a 15 year old Mk1 punto its worth the hassle/expense over buying another box? Thing is I can buy second hand boxes all day long for £30-40 a pop but its a gamble when you fit them that they function well. Its a lot of trouble swapping them out only to be disappointed.

A "recon" box is available on back order direct from Fiat - cost £1,766 plus VAT!