I have read a few posts in the past about the THUNK, and I think I may have it. I noticed a thunk while driving in slow traffic 20 to 30 mph, and the transmission? made a thunk while shifting. For just a second, I thought someone was tailgating too close and had bumped me. Is this the "THUNK"???

 

that's not the thunk i have. mine only "thunks" when i pull up to or take off from a stop. many times it doesn't thunk until i let off the brake pedal after coming to a complete stop. i find the "thunk" to be extremely irritating as it is more than just a slight sensation in my truck. on an especially hard "thunk", i swear the rear end of the truck drops slightly, immediately after the "thunk" is felt. anyhoo, sorry for the long post, but i'm getting impatient and pissed that this problem hasn't been fixed yet...been goin' on six months since i first took er in...

troy

 

Troy,

After reading how you describe your "thunk", I just thought of something that might help with the condition we have in our trucks.

If the rear end is moving back while stopping, the the drive shaft is moving back too. Once stopped, the driveshaft could remain out the tail housing say 1/4" and then when we launch the yoke must go back in the tranny as the rear of the truck comes back down. If the spline in the tail housing that matches the yoke is too tight, then it might bind and cause a jerking reaction and maybe that's what we are feeling.

I was wondering if a set of ladder bars would help. I recall from my racing days that ladder bars connected the rear end housing tubes back to the frame which keeps the rear end from moving back while accelerating or braking. Hmmm, I wonder...

Anyone up for a joint experiment?...Not that kind or joint either

~DM~

 

daveman,

you could be on to something. let me run this by you. when i have a bunch of weight in the box...say 500lbs...i've noticed the "thunk" being subdued. do you think the extra weight is keeping the axle wrap and/or fore/aft movement to a minimum?? also, your idea of the fit between the yoke and output shaft being too tight might explain why lubing the splines only works for a short time?? just throwing out some ideas. i'll definitely run these ideas past the rep whenever he shows up...!

troy

ps...if you wanna try the ladders, you have my blessing!!!

 

Any thoughts on why some SCrews have this "Thunk" problem and others do not? I am 6,000 miles into my second SCrew (a 03) and never had a thunk on this one or my 2001. If it were a specific design or engineering problem I would think it would be prevalent in all SCrews. Seems strange.

 

Troy,

With your blessing and all, to install the ladder bars as an experiment, you can send the $500 dollars to the following address:

Ford F150 PITA "Thunk" Issue Review Board
c/o DaveMan the Toolman
F150Online.com
Summerville, SC OU812

I have a Paypal account where the money can be sent as well, I'll be waiting please kind sir

ps, don't forget to book a flight too so you can assist with the install and log the results

Troy, I doubt that Ford is going to a damn thing cause if they find the problem it'll cost them a fortune to fix all the trucks and most manufacturers won't ever admit to any wrong doing, even if they know the issue exist and that they could fix it, it's just too expensive. One example is the radiator issue that was brought to light...My truck was built in April and people that bought trucks as late as May got the offer for a new bigger radiator or the money deals and since I bought in September, I got the shaft...

~DM~

 

Gentlemen,

I must be the luckiest person of all. I have both Thunking issues. I have the dreaded tranny thunk, @ ~18-20mph, delayed engagement into 2nd gear. As well as the shuddering and thunk when taking off from a stop. I have had it to the dealer about a 1/2 dozen times or more over the last 2 years for this thunking issue. And still nothing done. I just had it in yesterday, and this is what is now on my paperwork:

"customer states shudder/delay in rear end more from start up from stop." --> "Verified concern. Normal condition. Searched for TSB's, Considered normal operation at this time."

The service writer I spoke with acknowledged that this has been a concern from others for some time. He said that he even had a similar problem on a Silverado had had just traded in (he's new at the dealership). He said that Ford knows of the problem, but don't have a fix at this time. Now I don't know how much of that is actually true, or he was giving me a line. He was nice, and seemed to be truthful. At least they did acknowledge the issue, and didn't just say it's a normal operation. I'm just keeping everything well documented for any future problems.

Tom

 

Mine does after I slow down to 15 mph then get back on the gas , it feels like its in neutral for a split second. It does it fully load with six passangers and also pulling a trailer.
I 'll bring that up with dealer next time I visit them ,ust so thiers a paperwork trail.
I also have the piston slap issue with the truck just one more thing to add to long list.

 

Had a similar thunk problem in my 99' which was fixed with a new drive shaft under warranty by the dealer.

Have new 02 screw with only 350 miles...too soon for any problems I hope.

 

hey tom,

it only took ford 4 years to fix the driveshaft problems on the ranger...surely with the sales slogan going back to quality is job 1, they should be able to get that fix out quicker for the s-crew, shouldn't they??

daveman,

the monopoly money is in the mail!!

 

Troy,

You send the monopoly money Fed Ex, and the aluminum foil ladder bars will be rushed to you the same day, how's that for service

I always like to treat others as they treat me

~DM~

 

Hey guys, can anyone describe what the "THUNK" is??? Is it from a start, or is it at slower speeds??? I'm not clear on what the THUNK is that has been described here before. Thanks

 

Okay Marc,

The "thunk", for me at least, is when I come to a complete stop, accelerate and It feels like something slipped or jerked in the rear. It kind of feels like there is too much play or something but there isn't too much play. I can make it do this thunk every time I stop if I want it to. The worst is when I stop suddenly and then accelerate it's a real annoying sensation.

Another thunk or thud is when I accelerate to around 15 or 20 and then just let off the gas, I feel a slight clunk or thud in the tranny but I think that's more normal than the take off scenario I mentioned.

Does that make it more clear now?

You got the "thunk" from takeoff?

~DM~

 

Thanks DM. My thunk was while driving in slow Atlanta traffic. The thunk was so significant, I thought someone had bumped my rear bumper. I'll pay closer attention to it tomorrow but I don't think I have the thunk from takeoff. Thanks for the explanation!!

 

daveman et al,

strangely enough my truck has never "thunked" while at speed like some of you are reporting. mine is only noticeable right as i pull up to a stop, or takeoff from a dead stop. most of the time you can only "feel" the thunk...but when a really good one happens i can actually hear a mechanical clunk and the rear end will drop ever so slightly...