Like everyone, i accelerate hard when i'm getting on the highway, but when i go to put my car into 5th gear after doing this, it grinds the gear. I've tested my driving technique out many times and i'm very sure that i am not doing anything wrong. Does anyone have any idea why my car is doing this??? I've had to stop accelerating so much to get on the highway and that takes the fun out of it, plus the sound of grinding gears is giving me nightmares.