LUBRICANT FOR G56 TRANSMISSION:
There has been much controversy regarding lubricant selection, with many owners and industry experts arguing that using ATF+4 to lubricate the transmission, as Chrysler recommends, can cause it to fail prematurely. Mercedes-Benz recommends a thicker 75W or 90W gear oil in their trucks that are equipped with the G56. It is debatable whether anything is gained by switching to a 75W/90W gear oil, but many owners choose to do so. A tooth was removed from the input shaft gear for the 2007.5 model year, resulting in a ratio change for the 6.7L Cummins version. When equipped in 6.7L applications, torque was derated to 610 lb-ft for 2007.5 to 2012 model years, and has been derated to 660 lb-ft for 2013 to current model years. Meanwhile, the Cummins Turbodiesel is available with up to 900 lb-ft equipped with an automatic transmission.
