I've noticed a very damaging like-sound come from my truck recently, it sounds terrible! I have the 4l60e, it sounds as if the transmission is just grinding on the gear to shift, it'll make a terrible grinding noise when trying to shift from 1st to 2nd and then 2nd to 3rd. I dont know what it is, it'll make the grinding sound for about 2 seconds as if it was stalling, and then it'll finally shift. I have no idea what it could be, sometimes it doesnt even make the sound when shifting, and I just recently changed the transmission fluid and filter and everything seemed normal when I took a look at the fluid, barely any metal shavings or anything stuck to the little magnet on the bottom of the pan. if anybody has had this issue or could help me out, it would be greatly appreciated. Thank you!