Released in August 2004, the car debuted a new generation of 175 and 190 kilowatt (kW) (235 and 255 hp) 3.6 litre (L) Alloytec V6 engines in place of the older 3.8 litre ECOTEC V6 engines. These new Alloytec DOHC engines have carried on through to the Omega which was released in August 2006. A new 5L40-E 5-speed automatic transmission sourced from General Motors was introduced on the sports and luxury V6 variants.