Thank you for your purchase of this Transfer Case.Before installation, gear oil must be added to the unit.This Transfer Case is compatible with vehicles equipped with a 4L60E transmission and features a 27-spline input shaft.Front output has 32 internal splines with one tooth missing.Rear output has 32 external splines.Designed for shift applications from 1998–2002. Compatible With the Following Models: Escalade 1999–2000 Avalanche 1500 2002 K1500 Suburban 1998–1999 Silverado 1500 1999–2002 Suburban 1500 2000 Tahoe 1998–2002 Sierra 1500 1999–2002 Yukon 1998–2002 Yukon XL 1500 2000–2002 Fits OEM Part Numbers: 24228410, 12575125, 15007093, 15017351, 15017912, 15017942, 15037093, 15037351, 15039438, 15052506, 15709322, 15753790, 15761465, 15769438, 24228404, 12572904, 52800113, 412-426 Note: Please compare your existing part carefully with the product photo and listed OEM numbers to confirm compatibility. Disclaimer: This is a compatible replacement part.Any brand or model mentioned is for compatibility demonstration, not endorsement.