My tranny shifts hard from gears 1 to 2 and sometimes from 2 to 3. Resetting the computer oftentimes fixes it and makes it shift smoothly again, but it always comes back. I've replaced the throttle position sensor, and the prindle switch, but it's still happening. I've taken it to a couple of transmission guys, and the code that keeps coming up is 628, which is TQ slipping. I've also read some posts in here referring to the "vehicle speed sensor" that could be the cause, but I am unable to find that sensor on my truck. Is there anyone that could help me to find it? Is it possible that this sensor is the problem, or is it time to replace the torque converter? I have a 1994 F150 XLT, and I think the tranny is an E40D, but not positive.