hi all,i have an 02 vectra 2.2dti sxi,had it now about 6 months,have noticed a knocking/slap when changing from 1st-2nd-3rd,really noticeable going up a hill,took it to my local vauxhall dealer this morning,guy took it for a "run" he thought maybe engine mount as when you press accelerator quick then lift it off again you can hear a knock,backat the garage a mechanic took it,he thought it was a problem inside the gearbox,they sent me to their guy who repairs their transmission problems,he thought maybe either the 'floating' fly-wheel or 'spider-gears',can anyone point me in maybe the right direction as to what the problem(s) might be