I have a 2006 Cadillac DTS. While at the auto parts store I noticed drops of oil dripping onto the pavement. I looked around the engine area trying to figure out where the leak may be coming from. It is leaking on the passenger side and i noticed there was oil on the crossmember. Not sure if it could be the half seal or the rear valve cover gasket. Hoping someone may have an idea where the leak could possibly be coming from. Thanks