No offense intended but are you sure you have oil in your tranny? It should be splashing around onto the shift rails and the forks should slide easily. The top is just a little tricky getting back into place particularly the reverse fork so I would check to make sure there is oil and that would be a good time to make sure you don't have water in there. Loosen the drain and see if water drips out or oil. Mine was almost dry except for a couple of cups of water, all because the transfer case had a bad seal hence the oil mostly leaked out and the shifter cover was gone hence the addition of rain water. Took some serious flushing with diesel to clean it up.
Good luck.