Alright so, I was driving yesterday and while I was goin down the road at about 40, my speedo dropped to zero briefly and jumped back up. I thought I was about to blow a fuse but when I went to pull away from the next stop sign I had to put it to the floor to get it to go. My tranny was stuck in 3rd, I tried shifting manually and nothing worked. Turned the truck off for about an hour turned it on and now tranny seems fine? Anyone have any ideas what caused this?