Rep Power: 0

My 91 Honda dx automatic transmission sticks in the middle gear when cold. It will not shift into high gear until it warms up. When it is warm enough it will make a 1/2 second metallic rubbing sound and then will run perfect from then on. It has been doing this for two weeks now. I just changed the only slightly dirty fluid but it still does this. If i warm it up for 5 minutes it will work but almost always i have to hear the strange 1/2 second sound. I am wondering if it could be anything short of the beginning of the end!!!