I have a new 99 F150 w/4.6 and auto trans, but sometimes when letting off the gas, it makes a "clunk" or "slack" sound in the drive train, sometimes when reapplying power and letting off again, it will make this noise in rapid succession, does not do it at higher speeds, and turning off the OD did not stop it; does this mostly at lower speeds (under 50 mph) and moderate inclines; took it to dealer service, they said they could not find anything wrong.
Help needed, it is very annoying.

 

I have the same complaint. Dealer has told me that its normal, suprise, suprise.

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99 2wd S/C s/b XLT 4.6 Triton auto. w/3.08
BONE STOCK...for now

 

It is probally your slip yoke https://www.f150online.com/f150board...0237.htmlyoke. https://www.f150online.com/f150board...ML/000224.html Click on these, if they do not work go to "Other Drivtrain" and look on there for slip yokes.


[This message has been edited by ford-tough1 (edited 12-06-1999).]

 

Good luck with thatone. I hate to sound pessimistic (spelling right??) but I had a similar problem with my 98 f150 4x4. If you serch the archives you can find some posts under clunk on stopping. If I let off the gass, it would clunk. Sometimes, did not have to be hard acceleration, just normal acceleration or cruising. It would also clunk at 22 MPH while slowing. I don't beleive it is the slip yoke. Ford changed the slip yoke on the 98's. The TSB is supposedly for 97's, so the dealer says. Ford replace a tranny, transfer case, rear end gears, reprogrammed the computer, checked for loose nuts and bolts.... Finally looked at by the Ford engineer, who determined that "Was normal for this make and model..." Bulls...! Why do all the warranty work if ti was normal! But I rant. Sorry!! I fixed it by trading in for a Super Duty. After the truck started to crack, I didn't feel it was going to hold up over the long haul. I hope you have better luck. I procastinated as far as the Lemon Law was concerned. My mistake. It went in at least 10 times for the same thing. Noise was there from day one. One other thing I found on the NTSB web site under complaints was Ford had used the wrong motor mounts or tranny mounts ones for manny instead of auto or vice versa. Don't know if that was true or could be possible problem. Someone also complained of design of truck alowws raint o come in open window!! I kid you not!!! Good luck, don't make the mistake I did. If it's a normal noise, they should be able to tell you exactly what it is. & If they know what it is, they should be able to fix it! :-)

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Former 98 150 owner with all clunks, and some cracks!!! Now real truck owner!!! 99 SD Reg cab, 4x4 XLT, Powerstroker, auto longbed.