Steering in 4wd?????

When i lock my jeep into 4 wheel drve it is all over the place when i drive it. It acts like 1 wheel pulls it to one side and once you correct that it will pull to the other side it fishtales like no other when driving it.. any ideas...

what are you driving on? ice? what kind of tc case do you have?

It was'nt really ice just pounded down snow, but it is a stock tranfer case for an 1987 jeep cherokee