I have a 96 Dodge Ram 1500 that I can't get to shift into 4 wheel high. I went out this last weekend to go retrieve my treestands fomr the woods I hunt. As I was driving down the lane to the woods it got really muddy so rather than spin the rear wheels I just decided to cop out and use the 4 wheel drive. When I pulled the lever down to the 4HI position the indicator light came on and I heard a clunk clunk sound. (Sorry for not being more technical) I don't think the transfer case is engaging fully. I had friend look at the wheels as I rolled along at idle speed and he said the "clunk" came when the wheel made 1 complete revolution. I looked in the Haynes manual and it said that the linkage could be loose or the fluid needs to be replaced/refilled. I have not used the 4x4 in over a year (maybe more) but I have never seen any drips or anything that could be leaking. Has anybody ever had this happen and what did you do to fix it. The replacing/refilling suggestion seems very easy so I am hoping that is what the problem is but the linkage part seems alot harder to do myself. Any help? Thanks in advance.