BWP

I have a 94, F150 automatic trans, electric shift transfer case. I have a clicking noise coming from the drive train. When I engage the transfer case the noise gets louder. From that I an leaning towards the transfer case being the problem. The transfer case engages into 4 wheel drive. I don't want to continue driving the unit as is. Has anyone had a similar problem and if so was it the T Case causing the problem or something else. Your thoughts would be appreciated.

BWP