I went to audi dealers for some gear box oil. They advised that a 1999 1.8T quattro has a sealed system. Which means that the oil has to be refilled via the gearbox oil drain plug and requires a special tool that only audi dealers have. They also said it doesnt have a filling plug like most cars. Ive checked my gearbox and the drain plug is undone with a tamperproof spline socket and it also has what appears to be a filling plug wich requires a hex socket. Can anyone offer any information. Is what the audi dealers said correct?