Installation recommendation: Experienced technician; Includes our exclusive Smart Trim/Clutch Control valve assemblies and items to modify the C2 clutch piston for increased capacity and more durability. The C2 clutch is the weakest part of the early 5 Speed Allison; Addresses goes to neutral under load; 3-4 slip; burned C2/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 & kickdowns; Handles 500 Street Horsepower