Improving The ZF6
Chevrolet later adopted the ZF6 for use behind its Duramax 6.6L diesel as an option to the Allison automatic transmission. Chevy asked that certain enhancements be made to the ZF6 used behind its diesel. Enhancements included a different bell-housing design, no external oil pump, steeper cut gears and quieter operating noise. This transmission was the last standard transmission which GM decided to use in its light-duty diesel before abandoning all manual transmissions behind its Duramax diesels in the 2008 model year. Ironically it was also the last transmission which Ford used behind its 6.4L diesel. In 2011 Ford also ditched its manual transmission option for all diesel-equipped pickup trucks. Currently the 6.7L Dodge Cummins diesel is the only pickup truck to offer a manual transmission option.