I. OE Replacement Part:
261HD, 412-541, RTC261GHD1, 12581007
12576436, 12576437, 12579911, 12579912, 12579913
12581006, 12576435, 12581008, 12588518, 12588519
12588520, 15023640, 15039437, 15045471, 15046965
15046966, 15709254, 15709260, 15753788, 15753789
24228405, 24220410, 24220425

Input shaft (internal spline): 32
Rear output (external spline): 32

II. Compatibility:
Fit for 2001-2007 3/4 & 1 ton applications.
Replacement for 2001-2007 GM Trucks with RPO code NP2. This is the manual shift unit for GM trucks with 6.0L engines. It has a 32 spline input shaft that mates with the 4L80 Transmission.
Replacement for Chevy Silverado 2500 HD 2001-2006
Replacement for Chevy Silverado 2500 HD Classic 2007
Replacement for Chevy Silverado 3500 Classic 2007
Replacement for GMC Sierra 2500 HD 2001-2006
Replacement for GMC Sierra 2500 HD Classic 2007
Replacement for GMC Sierra 3500 Classic 2007
III. Note
Gear Oil Type: 75W-90
Thank you for your purchase of our Transfer case. Before installation, please be sure to add gear oil to the transfer case. Failure to add gear oil before installation can damage the product and may lead to premature failure. Please note that we will not accept returns or claims for products that have been damaged due to improper installation.