markets. S 65 AMG was introduced in 2005 with new enlarged 6-litre V12 engine developed specifically for Maybach 57S and 62S (as to amortise the cost of engine development). The twin turbocharged 6-litre V12 had output of and of torque. S 65 AMG became the most powerful S-Class ever built with incremental power increase for W222 S 65 AMG in 2017. Additionally, S 65 AMG was world's most powerful five-passenger four-door sedan until Dodge Charger SRT Hellcat with was introduced in 2014. The S 320 CDI was initially fitted with a || engine, which was upgraded in late 2002 to a || one. The S 400 CDI had at first, but got in 2003. The type designation S 400 CDI was changed in the W221 generation to S 420. W220 was the first generation of S-Class, where automatic transmissions were standard on all models. At first, all cars had 5-speed 5G-Tronic transmission; however, since 2003 (2004 in the United States), S 430 and S 500 were instead offered with the new 7-speed 7G-Tronic transmission. Transmission All model years used a 5-speed transmission until a 7-speed came out. In the U.S. market, the 7 speed was the standard transmission on RWD S 430 and S 500 models in 2004, and optional on 4MATIC models. V12 models continued using the 5-speed as the 7-speed could not handle the immense amount of torque from the V12. In 2005, the 7-speed was standard on the S430 4MATIC, making it no longer optional. The transmission has W and S modes that can be selected. See also: Mercedes-Benz 5G-Tronic transmission and Mercedes-Benz 7G-Tronic transmission Certificates and reports In 2005, the S-Class was the first vehicle to receive a TÜV Institute environmental certificate from the German Commission on Technical Compliance for environmentally friendly components. The improved environmental efficiency of the W220 manufacture process was judged approvingly. Edmunds gave the S-Class a 5 out of 5 reliability rating and MSN Autos assign an expert rating of 9.0 out of 10. By March 2011, Consumer Reports had changed its reliability ratings for the 2001 and 2002 S-Class as having improved to "average". Build quality was generally considered to be good. For instance, Forbes described the W220 S 500 as "built remarkably well." Early W220s were recalled for issues with the trunk spring and the hydraulic fuel line; there were no recalls for the 2005 or 2006 model years. Recalls