FL3.2TL

Im really scared now, I dont drive my car hard as in shifting throw every gear everytime, if the only gear I would shit before redline would be first and thats it. Now, my first gear and only my first gear in auto gives a jerk that you can hear, but the other gears are fine!, like it would shift fine. Now in SS, it doesnt do that. Should I change my fluid, I only got 72K and I dont think its my tranny though. Got a 1999. Let me know asap!