I have no tonneau cover. My truck has just passed the 60k mark and I don't really beat it up too bad. The slip yoke could possibly be the culprit of the noise. I know that it's "extending" really anytime the frame is flexing or you're accellerating as it makes up the wider gap in the driveline as the rear end torques upward ever so slightly. That would explain why it makes more "clunks" whenever I drive up my sloped driveway slowly. If I were to guess, it probably clunks about three or four times if it clunks at all. Other times it has only clunked a single time and not as loud, and if I'm lucky, it sometimes doesn't do it at all. During the summer it has gone a couple weeks without doing it. But if it was the slip yoke, wouldn't it be doing it all the time?

 

Ya like I said, it seemed fine when I checked it a while ago, I was meaning that more for a seperate problem. I just had it undercoated not a month or so ago, and if memory serves, for a while after last time the clunk was there, when it dries it may go away. Just another stab in the dark. Really though if it was a u joint or something like that, you'd know it so thank God it aint that.

 

Blue20004x4,

Where are you located? I live in Windsor. We should meet up and have a coffee. I could listen for your clunk too.

JMC

 

JMC, I'm located on the east side of Windsor. I think I've seen you around. Do a bunch of you guys hang out around at say tim hortons during the summer? Maybe I'll stop sometime and throw around some b/s with everyone about beatin' dodges and toyotas- gutless. As far as the noise, I'm clueless as is Bobby from Minnesota. Today, didn't make a sound and actually felt more like a new truck. If something is wrong or overlooked, I will post because right now I can't even really duplicate the problem.

 

Yup, we hang out at the Timmy's next to the Red Lobster on Tecumseh. Look for a 2000 Toreador red Extended cab flairside 4X4 mine, or a White 99 reg cab flairside 4X2 Neal's or a 94 Blue extended cab long box 4X2 Izzy Eddie's.

JMC

 

Just talkin' to Neal on another thread and he said to meet up at the same spot. C you guys there sometime.

 

my 96 150 had that clunk, the lower shock bolts wore and rusted inside the shock letting them move slightly at times. new bolts probem solved

 

Thanks for the info Becker. I was planning on replacing the shocks anyways this summer and ill be sure to do the bolts too. Even though your 96 was a generation before mine I don't think Ford changed too much in the way they mount the shocks to the axle. Lets hope that works. Thanks

 

is it possible that your hearing the clutches in the rear gear?

my old 89 F-250's rear end would clunk going around corners
you could actually feel it in the seat

just another opinion

...zap!

 

Hey, new to the forum and stumbled on this thread. I have the same exact problem as BobbyRutt. I've been dealing w/ it for about a year now, taking it to the dreaded local dealer to no avail. Started with only 19k on it, I now have 27k. They changed out my clutch packs per TSB, did not fix it...Checked torque on all bed bolts, all good...I replaced my shocks with some Ranchos and torqued every bolt under the bed that I could see, noise still there. Final verdict from Ford "normal characteristic of an F-150", yeah right! I finally decided to take it to another dealer who would take me seriously. They heard the clunk and found "excessive play in rear axle". Replaced both rear axle bearings, did not fix it. Taking it back in two days to see what they can find. Mine too seems to do it less with a full tank of gas. I especially hear it when I back out or drive out of my driveway. I live on a cul-de-sac and have a curving 4-5 inch curb so my tires come off at different times causing my frame to flex, I'll hear it after the rear tires drop off and then again after the front tires, sometimes it's only one clunk, sometimes 3 or 4, temp and humidity definately play a big factor. I think it has something to do with a body mount or some other rubberized/plastic part allowing metal to metal contact. Could it be the leafsprings ends shifting on the attach bracket, I can't move them by hand, but then again I can't simulate 4500lbs flexing. I'll let you know what the dealer says, I hope they can fix it, my warranty runs out at the end of this week!

 

Like I said, it seems to be temperature and moisture related, cause today, nice day about 70 degrees, all is quiet. I'm all ????????? and this has been going on for more than 2 years I'd say.

 

At one time i had fixed a few vehicles with a noise like that but cannot remember if it was a Ranger or a F150 but it was the slip yoke on the drive shaft that was causing a slip and stick situation and could change with moisture and load . It was a very easy fix all i had to do was take the shaft down remove the boot straps seperate the 2 ends of the shaft and i applied teflon grease to the splines. put it all back together and the clunk was gone.
I hope this helps someone.

 

Your on to something here because somewhere i read that by greasing the yoke you get rid of the clunk. They meant more when you leave a stop and get a clunk. Basically what your saying is take the d shaft down, load the spline at the end of the tranny with teflon grease, slide the d shaft back and we're good to go.

 

last time i checked you can't actually buy teflon grease anymore. teflon never breaks down and they found it in the middle of the pacific ocean yadda yadda yadda so now teflon is very bad stuff.

ford now has this stuff called ptfe lubricant which apparently doens't contain teflon.

you don't need much to stop the clunk from happening. mine is usually good for about 2 months after applying about 1/3 of a tube to it.

 

Hey sparky, I see you live in Langley. I was out there last June and drove around and saw Fort Langley. BC is nice, the old lady's from there, Maple Ridge. Anyways, this clunk has to be suspension related because everyone seems to be sayin that a full tank quiets it considerably. Also, on the front of your leaf springs is a steel band, one side is loose, passenger side, and driver's side is tight. Passenger side is noisy. Did the 280 pounds jumpin in the bed test- scientific! So I pushed the band forward till it was tight. We'll see. I am going to grease that slip yoke and get rid of that problem if not just for the mean time.