Clunk Clunk Sound.

Discussion in '2005+ Mustang GT 4.6L Tech' started by OLD 96, Oct 22, 2022.

  1. OLD 96

    OLD 96 Junior Member

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    2008. 72,500 miles. Original suspension. When I shift gears at lower rpm in lower gears I hear a clunk sound coming from the rear area of car. If I shift at 3 grand or higher I don't hear it. If anyone can point me in the direction in what to look for would be appreciated. Thanks.
     
  2. Danny Paladino

    Danny Paladino Junior Member

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    Could be the stock 2 piece driveshaft. A clunky, over engineered solution to a problem that didn't really exist.....these cars should have come with a 1 piece shaft (frpp and aftermarket companies offer these)
     
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  3. 07 Boss

    07 Boss Senior Member

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    There has always been a little slop in our drivetrains. If it is getting worse, Like Dan said it's prolly the driveshaft. That carrier bearing in the middle is prolly got some play in it.
     
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  4. nfrizell

    nfrizell Member

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    1 piece driveshaft would be my first move also.

    Sent from my SM-S906U using Tapatalk
     
    OLD 96 likes this.
  5. DieHarder

    DieHarder Senior Member

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    You might want to get it up on jackstands/lift (securely) inspect for anything obvious/see if the driveshaft has any play and if needed ask a friend to run thru the gears to see if you can recreate the clunk and determine approximate location. Could be anywhere along the drive line; u-joints; differential; etc. Other possibility is the differential upper link (rubber) may have perished. Worth a look IMHO.
     
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  6. OLD 96

    OLD 96 Junior Member

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    Thanks for all the help. I just had the pilot bearing and throw out bearing replaced about 1000 miles ago. I asked the shop about drive shaft and bearing. They said it was ok. But. Hey. Ya never know. The question. Lots of choices on shaft. Steel, aluminum ,carbon fiber. I am going to stay with stock HP. I don't race. Am on a budget. I see Amazon has Ford M-4602-MGTA for $662.99. Looks like a good choice. I guess I'm looking for any validation. Thanks.
     
    Last edited: Oct 23, 2022
  7. Danny Paladino

    Danny Paladino Junior Member

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    Yes, that's the one you want
     
    OLD 96 likes this.
  8. Laga

    Laga Senior Member

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    Once you get under the car, grab the driveshaft with one hand. If you can do this, it needs to be replaced.
     
  9. Unexplodedcow

    Unexplodedcow Member

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    I'm going to hazard a guess at gear lash - many of these cars have heavy gear lash in the rear ends (my '10 GT with 3.73s does it pretty badly). I had an '07 V6 that made the same clunks, but milder. Switching to a 1 piece driveshaft helped (less mass), but it still clunks.
     
    OLD 96 likes this.
  10. OLD 96

    OLD 96 Junior Member

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    That thought crossed my mind also. It was more prominent when I let my son drive it. He can drive a standard. Just not used to Mustang. Shifting at low rpm and chuncky on the clutch. When I drive it not so much. As you mentioned. In like cruising 3rd gear let off gas and then give it gas I can hear small clunk. Sounds like the gear lash you mentioned. I'm recovering from a knee injury. When I get better I'm going to jack up the rear end and check out DS and bushings on linkages. Thanks.
     
  11. wdrlaw

    wdrlaw Junior Member

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    Find it now, before you bolt anything new on. In order, I added to my 2009 GT: CAI and tune; shifter; Ford Performance handling pack (springs, struts, shocks, F&R sway bars, panhard bar); GT 500 front control arms; adjustable rear third link; adjustable rear control arms (poly + spherical bushings, per the late great Norm Peterson); spherical bushing for third link; one-piece DS; FP 4.10 and LSD. Somewhere along the way, probably after the handling pack, I developed a bad clunk in the rear suspension or driveline. After spending more time on my back than I want to remember and re-torquing every bolt 2-3 times, I couldn't find it. The shop I trust (who installed the third link bushing, new gears, and LSD after the clunk started) could not find it. It was not gear lash, but some jackass later told me it was and charged me several benjamins to "fix" it. Still clunks. I desperately want to track the car but I don't trust it. I have learned a very expensive lesson: Do NOT continue to bolt parts on in the hope they will fix the problem. Identify the problem first, then fix it. Maybe the fix will be a bolt-on like a one-piece driveshaft, maybe not.

    BTW, please post if you figure it out. I'm still looking for mine. Thanks, and HTH.
     
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  12. JC SSP

    JC SSP Junior Member

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    Everyone here has mentioned some pretty good options (weak 2-piece DS and gear pinion lash).

    Don't forget to look at transmission mount and any other associated bushings in the rear (i.e., upper differential mount, both lower control arms, exhaust system/hangers, etc.) Some cars with oil leaks (not saying your car has one) can deteriorate bushings if contaminated.

    I personally would do a visual check before removing or replacing any part. Inspect for damage & play then move on to the next part... Obviously, some parts like gear pinion lash will be more extensive and complicated to confirm (remove diff cover and use dial indicator to confirm specs), but this should be at the bottom of the preverbal list.
     
  13. Juice

    Juice forum member

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    Every manual trans car I have owned did this to some degree. My bikes have some slop too. Dont over think it and chase ghosts.
    I have 3.73s w/.012" gear lash. Jpc aluminum one piece drive shaft (slip yoke), magnum xl. I know everything is in great shape. It has some clunk.
     
  14. 07 Boss

    07 Boss Senior Member

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    Here's another thought. Since you said original suspension I would check your upper bushing on the diff that the upper control arm bolts to. Even when I upgraded my suspension this was one of the things I didn't replace with aftermarket stuff. I ended up replacing it when I saw how tore up it was a couple of years later. But this can cause a cluck as the rear axle rotates against it.

    This was my stock bushing after about 6 years (9 years ago) and 50K miles.

    [​IMG]
     
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  15. DieHarder

    DieHarder Senior Member

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    Yeah, that one's an absolute bitch to replace (must drill & cut out the rubber) but after an afternoon finally got mine out and pressed in a urethane bushing from Prothane. Don't remove the outer metal shell; you have to reuse it. Worth the effort IMO.
     
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