Revmax / Transgo Shift Kit for Allison 1000 2004.5+. FEATURES: Corrects /Prevents /Reduces :Goes to neutral under load; 3-4 slip; burned C2 or C3 clutches; sticks in one gear; won't move after extended parking; loss of pump prime; smart clutch control valves for increased durability; SHORT -CRISP -SMOOTH -upshifts and kickdowns. Make: GMC, Chevy. Model: 2500HD, 3500HD, Silverado. Year: 2004 ,2005 ,2006 ,2007 ,2008 ,2009 ,2010 ,2011 ,2012 ,2013 . Engine: 6.6L Duramax Diesel.