[Jimma1020]

So the other day I was driving to my storage locker about 30 miles away. All of a sudden my rpms would shoot up to 2000 rpms then back down to 1500 . Slowly they would go up higher every time. On my way back I was about 2 miles away and I lost 3rd and 4th a presume. I would be going 20-25 and it felt like it would be shifting up to third but would shift down to 2nd running 3500 rpms. I had to go 20 the rest of the time. Finally I got home and realized my dipstick tube wasn't in the tranny and must have lost oil. So I got it back in and added more. Thought it was the filter and oil so dropped the pan and replaced it. Still nothing. Thoughts?