4 wheel drive doesnt engage on 1999 Chevrolet Silverado 1500

ive replaced front axle actuator and i can hear the transfer case motor working and can feel 4 low engaging and when i jack it up off ground the front drive shaft is turning but in the snow the front wheels arent pulling transfer case fluid is full and so is front diff. its a push button selector and all lights are working like they are supposed to ,,,,,,,,,,,any suggesting......

Asked by for the 1999 Chevrolet Silverado 1500
scan for codes and post so we can adv
ok will try to do that soon