I took my truck into ford a while back about the transmission clunk, when ever you go from cruising to no throttle then back to gas, but it didn't happen every time and they said it was fine. Now I am out of warranty and I can get it to do it every time what could it be? Is that really bad or am I over worrying about it. Also it does it with my edge on or not, its not the TC lock-up clunk common with the edge, I have that one too, this is mainly at low speed. I get it really bad going though speed bumps, gas then let off to go over the speed bump then gas again and it will clunk almost every time.

 

Wow. Old thread but what was found or does anyone know of this problem. My 08 screw 5.4 4wd 5.5 bed does this exact thing.

 

Yeah lets re-vive this one!!
I have the same clunk when accelerating and about 10mph i hear a clunk..

 

Slip joint clunk. Haven't read about it for a while but it used to be discussed ever so often. Ford even has a special grease for it. Some guys had it greased under warranty and had no more problem, some other had it return before too long. I believe there was an issue with the machining in the slip joint grooves, maybe a touch too tight or something like that. I don't remember them having the problem before the '04 NB. Maybe Ford loosened the machining of the grooves a couple or 4 thousands to eliminate the problem along the way, don't know.

 

I will try this when I get back from traveling for work..

But it sounds like its gonna be an easy fix so now im scared! That never works for me...

http://www.ford-trucks.com/forums/82...te-stop-2.html

I hate linking other forums but searching what you said I found this.

 

If the clunk is in the rear end then try adding a tube or two of special rear end "additive" for rear differentials. Ford had some issues with the limited slip clutch pack not releasing. Should be a TSB out for this as well. Most noticeable when slowing and turning slightly right then accelerating.

 

My dealer tried lubing the yoke on my 05 and it worked for a little bit but the issue came back. When I took it back in the replaced the drive shaft and that did fix it for me.

 

I'm well out of my warranty but any idea how much a new driveshaft installed would be? Do you have some kind of part number for that?

I've had the clunk for 6 yrs now. Can pretty much tell when it will happen now and I just ease off the gas a little to let whatever parts catch up and then accelerate and all is fine. I've actually gave it gas before and knew it was about to do it and said the heck with it and gas it and heard grinding noise like gears.