Does your's do it from a take off on flat pavement? Mine does not. It only makes it on uneven pavement when I'm turning.

 

Not from takeoff. Mostly it happens when I am coasting and re-apply the throttle or when I am going around a corner and re-apply the throttle. It is definitely the slip yoke. As soon as I grease it (inside and out) it goes away. I did just replace the stock shocks also. I could not believe the difference in ride afterward. The clunk also seems to be less noticeable even though it has nothing to do with it.

 

This thread is mentioning 2 different and distinct problems. First (see the4by4freek's post) is the slip/bump felt immediately before coming to a complete stop, as well as when taking off from a stop. This is caused by the slip yoke, and is fixed either by applying a specific grease to the slip yoke (if no metal shavings are found on it) or by replacing the entire driveshaft. I had the 2nd option done back in 11/2006.

Now the 2nd issue in this thread (see m249bb's post) is what I'm currently experiencing. When tuning or swerving (or doing anything other than going straight on a flat road), I hear/feel a clunk at the rear axle. I can duplicate the issue by pushing on the bed, making it sway side-to-side. It's definately the axle moving. This happened on an Toyota pickup I used to have, and was told by the dealer that it's normal for semi-floating axles. However, on my F150, the issue just developed over the past 1500 miels. Something had to of worn. But, to m249bb's credit, I did just get new tires, load range D (8 ply) around the same time. So maybe its just that the older p-rated tires were absorbing most of the clunk... At any rate, it's quite anoying. I wish like heck that there was a fix for it. Does anyone have any ideas??????

 

I agree that 2 different problems are being discussed here. I was able to get rid of the clunk sounding like something sliding around in the bed by tightening my rear shackle bolts. I took them up 1-2 turns and the sound went away. Just don't tighten them too tight or that will cause them to bind and give you another noise.

 

Thanks, I'll try that. Some people think it is the rotor hitting the pads/caliper, but I have a hard time understanding how that can be.

 

Well, in an attempt to get the noise to go away, I jacked up the truck tonight and checked the torque on all the bolts on the leafs. To my surprise, all 8 of the u-bolt nuts were under-torqued. They weren't anywhere loose enough to turn by hand, but they certainly weren't up to spec (which is 98 lb-ft). I'd venture to guess they were in the ballpark of 60 lb-ft. Anyway, I put my jack under the axle, and proceeded to loosen the nuts until they were completely loose. I used the BFH and straightened all my leafs, as a few were misaligned). I re-torqued all back to factory spec, which requires torquing in 4 stages (26 ft-lb, 52 ft-lb, 74 ft-lb, 98 ft-lb). I also checked the torque on the shackle-to-frame bolts, and they also were not tight enough.

Anyway, I have no idea if this will take care of the clunk, but I feel better knowing that the rearend is now tightened to specs. I suspect that what I did will NOT fix the noise, as I can easily replicate the sound by pulling on the rear wheels when they're off the ground. Oh well...

 

i took my truck to the dealership and they replaced the clutch packs in the diff under warranty, sound went away for a day and then came right back. this was about 2 weeks ago and now it is louder and more prevelant that when i originally brought this thread back

im trying to sell my truck and this is really annoying

 

I'm still chasing the noise. I tightened the rear shackle bolts as someone suggested. Noise still present. Changed the rear dif fluid to royal purple. Noise still present. Removed Spare tire, noise still present. Regarding the effect stiffer sidewall tires may have, my truck has made this noise with the stock c rated goodyears as well as a set of e rated Michelins.
Going to try the following:
1. removing rear shocks-
2. removing front sway bar- maybe endlinks are bad
3. tightening u-bolts
4. loosening rear shackle bolts.
5. tigthening front spring bolts.

That clunking some are hearing when you rock the truck side to side is in my opinion not what I am hearing. I have to really rock the truck side to side. My truck is not rocking anywhere near this amount when I hear the clunk. I cannot duplicate the noise except when driving at low spead and turning.
It does sound like it is coming from the rear, but sound can travel. Any suggestions welcome.

 

I agree that it takes some effort to rock the truck to get the noise to happen... But when it's jacked up, it is very easy to duplicate the noise. Just gently pull/push on either rear wheel, and it happens every time. I still think the sound (at least mine) are the rear axles "floating".

 

mine too but its getting worse daily

 

You may be right. But to me it sounds more like something is in a bind and then releases. Also I noticed that sometimes it does it when I am going in a straight line.

 

Add me to the list with this sound. Got an 05' and have been hearing this while turning at low speeds for a few months. It's not the driveline clunk I had where I would hear the clunk while accelerating from a slow speed once the tranny dropped gears. This sounds like suspension somewhere. I've looked everywhere. Don't see anything loose but some bumps and clunks can be heard and felt with a tight suspension if just yanking on the parts by hand. Being these trucks have sealed everything instead of having grease fittings, it doesn't surprise me. My truck is out of warranty and is almost paid off. I'm going to just drive the da-m S.O.B until I either start seeing sparks flying or smoke/fire in my rearview mirror. I'm tired of chasing every pop and creak these trucks have. It's not just Ford, it's all the makes. I'm going to drive it until it breaks then worry about it. Besides the basic preventative maintance, screw it IMO. It's funny that we worry and treat our trucks better sometimes than our our bodies. Laugh, but it's true.......

 

Did this do anything for you? Today I removed the rear shocks. Noise still there. (put them back). Tightened the ubolts, but didn't see your torque stages until afterwards, noise still there. Lubed drive shaft with correct grease, noise still there. Tightened shackles, noise still there.

Something I found. If you really want to cycle the rear suspension, take the rear shocks off. I was albe to really get the leafs moving. Funny thing. They were as quite as can be. I can only reproduce the noise while driving. I am starting to think the noise is the limited slip in the rear end or maybe a u joint getting ready to go out. It is starting to do it every once in a while when i am coming out of a turn and have already straigtened out.

The search continues.....

 

i too have this problem. i was under the truck tonight and was pushing up and down on the frame by the rear leafs. to me the noise seems to be coming from the actual leafs. i put one hand on the leafs towards the back bumper and could certainly feel the clunk. move the truck up and down not side to side
side to side= axle up down =???? driven me nuts 2 by the way

 

Have had this same problem, for a long time now... But mine seems to come from under the front floorboard, so more towards the front. I can actually kind of "feel" the clunk when I turn, under my feet. I have gone over everything a few times now and never found anything loose.

Guess it's time to start checking in the rear. Which I have gone over too, many times. Never tried the diff side to side thing though... Maybe it just sounds like it's coming from the front?

Could you feel the diff moving, or just hear it?