Hey, this is my first post on the forums. Just yesterday I bought a 2003 F-150 Supercab with the 4.6L V8 and an automatic with 114,000 miles. Of course, right after i bought it and proceeded to drive it home the truck started surging/bucking when in overdrive. If I turn the overdrive off, everything is fine. When I got home I put it in park and checked the trans fluid and it appears to be roughly 2+ quarts over full. I figured i'd probably take it in for a flush and have it filled to the proper level, but before I do anything I was hoping I could get some advice here. I'm fairly mechanically inclined, but I know nothing about this transmission. Thanks for any advice.

 

The first thing I'd do is siphon out the excess.

Was the bucking at relatively low speeds (45 or so) and light throttle opening? If so, it's tuneup time, that's a low grade misfire.

 

hey it might be the torque converter shudder if u go down the road and go to give it gas around 40 or so dose it fill like the truck is shacking apart and when u get pass that point its ok if thats what it is doing than go to a trans shop and tell them to change the fluid and drain the converter and put what they call shudder fix in it and that will stop ur problem

 

I changed 7 of the 8 plugs and coils, going to change the 8th tonight (needed a different tool) and I think the problem is already fixed. First off, I've been reading on here that the Autolite 104's are a no no, and that's what someone had in it. I'm guessing that the big problem was the coils though, so I must have fixed that swapping out the first 7 (well, all but cyl #3 on the drivers side). So i have a bit more driving to do before I can say it's fixed, but I believe all the people on the forum that mentioned a low grade missfire in response to others having this same issue nailed it. Thanks to both of you who responded and i'll report back once I get a few more miles on it. I'm also planning on doing a fluid exchange just so I know there is good fluid in the tranny/converter.