This direct replacement clutch servo restores the pneumatic pressure boost needed to reduce the effort required to activate the clutch pedal. It is engineered and quality-tested to match the fit and function of the original servo. Vehicle model years this part fits (be sure to check your vehicle trim using the Amazon garage) - [Kenworth T680: 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021] - [Kenworth T880: 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021] - [Peterbilt 567: 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021] - [Peterbilt 579: 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021] - [Peterbilt 587: 2013, 2014, 2015, 2016, 2017, 2018]