Is it normal to have to replace multiple gaskets, other than head gaskets, on a 98 Outback, AT, with 80,000 miles? My dealer tells me I need to replace the trany separator plate gasket, valve cover gaskets and 2 or 3 others...to the tune of $2000. We're starting with the trany separator ($800) since it leaks the most and on the exhaust - that stinks.