The oil pan on my 1998 A8 was leaking so I ordered a new gasket. The old one looked fine, but I installed the new one and torqued it properly. IT STILL LEAKS! Any ideas on what to try next would be appreciated. My manual mentions a silicone sealant, but does not mention a gasket. It appears that this may be an alternate method, but perhaps not with a gasket. The gasket I removed (which I believe was original) showed no signs of silicone sealant.