I have a 2001 Lariat super crew that is what i can only describe as lurching forward at about 45mph just after it shifts into third wondering if my transmission is shot or if it might be something smaller. Any help would be appreciated thank you.

 

I'll bet it is the torque converter locking that you are feeling. If the trans fluid gets old and worn out (yes, it wears out!) the lockup will get harsh. New fluid will fix this if I'm right.