Check out this site. Their chart says that transmission is a 99 model year. Maybe that trans wan't the original for the suburban. Or they are jerking you around. What was wrong with your trans? Just remember if you buy junk you own junk.
http://mmerlinn.com/catalog/lilscribbs77/gm_9l6/gm9l6010.htm
9LUD 99 4x4 Bell = 24206579, No dust cover Case = 24207965, NSS threads Valve body = 4209354 Cheese plate = PC 5 Solenoids, 8134 Pump body = 24201073, PWM Stator support = 24204705 Input tip 2KCD 02 4x4 Bell = 24206952, No dust cover Case = 24207965, NSS threads Valve body = 4216995 Cheese plate = ITC 5 Solenoids, 8134 Pump body = 24201073, PWM Stator support = No input tip