Transfer Case Assembly AP02 NP261XHD Compatible With Sierra Silverado 2500 HD 3500 Classic 2001-2007 Models With 6.6L And 8.1L Engines For Floor Shift Configuration Specifications: - Input Shaft (Internal Spline): 29 - Front Output: 32 (Internal Spline, one tooth missing) - Rear Output (External Spline): 31 OE Number: NP261XHD, RTC261GXHD1, 24228406, 12579907, 12581002, 12588514, 15023641, 15772804, 24238186, 24238839, 412458, 412542, 412604, 412-542 Will fit Following Models: - Fits 2001-2007 GM Trucks with RPO code NP2.This is the manual shift unit for GM trucks with the 6.6L & 8.1L engines. - - Silverado 2500 HD 2001-2006 - - Silverado 2500 HD Classic 2007 - - Silverado 3500 Classic 2007 - Sierra 2500 HD 2001-2006 - Sierra 2500 HD Classic 2007 - Sierra 3500 Classic 2007 Compatibility Disclaimer: This is an aftermarket replacement part.Any brand names or model designations mentioned are used solely for the purpose of demonstrating compatibility.