Just thought I'd let you know.. I just fixed this same creaking noise on my Dad's 98 F150. I'm sure there are multiple causes for creaking, and I first tried Lubing the Ball Joint but that didn't fix the problem. It turned out to be old front sway bar/stabilizer bar bushings. The front sway bar is the big round bar(about 2 inches thick) that runs across under the front end, probably a little bit rearward of the radiator. Just look under the front end, you can't miss it. There's too big Rubber bushings around the bar(one on each side), that are bolted to the frame with big U-shaped clamps(two bolts hold each clamp). Just remove the 4 bolts (2 for each bushing), and then the bar will hang down just enough to pry the bushings off (they're split and just wrap around the bar). Once removed, just coat the inside of them with some Grease from your grease gun (I used the same Grease I had for the ball joint) or I have heard of others using white lithium. Then just pop the bushings back around the bar, and bolt them back up. It's a quick simple fix. I'm sure you could replace the bushings if they fall apart, or you just feel like spending some more money, but Lubing them worked great for me. No more creaking. Good luck. And here's a link to some pictures of Sway bars, showing the two bushings.. from various years/models of the F150.
http://www.autozone.com/autozone/rep...96b43f802e4ca9

 

I tried wd40 on everything I could find on my 2007 F150 to squirt it on to no avail. This squeak has been going on for 2 years! It is a high pitched squeak that happens on every bump it Michigan's terrible roads. I finally laid under my truck while my son jumped up and down on the tailgate. I found my squeak!!!! The rear strap that holds the fuel tank was loose and causing the sound. The bolt that is attached to the frame had torn out the threaded insert that holds it to the frame. I replaced it with a nut and washer(with great difficulty) and no more squeak! Plus now my fuel tank is not likely to fall off, too. If this is your problem, have fun replacing this nut. I had to fish it through the end of the frame which is accessible from the drivers side rear wheel wheel. I attached the washer and nut one at a time to a magnetic flexible parts retriever and slide them over the bolt inside the frame. The bolt has a reduced radius on the end which allows you to drop the nut and washer onto the bolt. You then need to slide a 17mm open-end wrench onto the nut through end of the frame to hold the nut while you tighten the bolt. Have fun!

 

My 2000 4x4 did that. I ended up replacing the upper control arms and lower ball joints. No more squeak and squawk. Located the parts online for $65 and free shipping. Can't remember what site now, but I paid less for both sides than I would have paid for just one upper control arm at the local parts house.

 

Same happened to me after running through high water. It is so embarrassing in my opinion!! I had my son jump up and down on front end and back of truck while i was underneath located the squeal which was coming from both front end A-Arms the thng that holds the wheel to the frame. It was the joint closest to the wheel. Mine has a little cover over the joint which I peeled back with a screwdriver and with a grease gun squirted it with so much grease. The squeal was gone.....while I was at it...i went ahead and grease gunn all the bushings and joints etc I could......doesnt squeal anymore!!

 

My squeaking cones from the A-arm where it pivots up and down, engine side of the arm. i think the bolts that hold it in place go through a rubber bushing, like the upper control arms. if you try and lube it, it will be fine for a couple days, then will be louder. apparently, the only thing that works is that atp at-205 seal repair. it undries the old parts.

 

Holy Old Thread Batman!