Most likely valve cover gasket, but check the CV boot too, they have also been known to let go. New axles are about $80.00 at the auto parts store.
178,000+ miles, 5/20/12 new ej257 short block, 8/20/11 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. CHECK your oil, these cars use it.
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