I have a 01 Dodge Ram 1500 when I lock it into 4 wheel drive the light comes on but I get a clicking sound in the front end and if I'm on slippery surface the 4 wheel drive will slip, any suggestions or comments is greatly appreciated.

 

Might want to post in the second gen section. Your truck has a cad unit that is controlled by vacuum. Check that you have adequate vac to the unit. With out it it may not be engaging completely.