This Allison Valve Body kit is designed for 2006-2009 LBZ & LMM Chevrolet/GMC 1000, 2000, 2400 Heavy Duty, Work, Tow, or Race diesel trucks. This kit corrects, prevents and reduces the Allison transmission from going into neutral under a load, 3rd to 4th gear slips, C2 or C3 clutch burning, sticking in one gear, and so forth. This kit allows customers to experience short, crisp, and smooth up shifts and downshift. Kit includes all instructions for a trouble free installation.