I have a 1997 Ford F-150 flareside extended cab 4.6L V8. I was doing a U-turn one day and heard a loud pop, I don't know if this has anything to do with the problem but after 30 min. of driving the truck started whining a little high pitched and grindy at the same time. The next day it came and went or was very faint. The day after that, the truck was making the noise consistantly along with losing power between shifting, it would rev up a little and then slowly shift up and go. What does anyone think it is or may be? I think I need a new tranny, hopefully it can just be repaired but idk. Let me know. I am going to get it professionally checked out but just want some opinions, thanks!!!