4 Wheel Drive/SUVs: 4wd, push button switch, chevy silverado

Question
Hello i have a 04 chevy silverado 4wd, in the gauge cluster display it reads "service 4wd" i have checked the front actuator, the push button switch, the fuse and the electric motor on the transfercase they all work? any ideals would be appreciated. When i say i checked them i have another truck just like it and they work fine on there. thankx in advance

Answer
The service 4x4 light comes on at so many miles reguardless according to the owners maual I read on like and 05 or 06 , wanting you to service the transfercase. I just had that happen the other day. You can also scan the transfercase with a scanner to see if it has any codes in it . thanks ADAM