Slapping sound when shifting gears

Discussion in '2005+ Mustang GT 4.6L Tech' started by wdrlaw, Apr 7, 2021.

  1. wdrlaw

    wdrlaw Junior Member

    2009 GT 5-speed. Hurst shifter, FRPP handling kit (shocks/springs/struts and stabilizer bars), and Steeda adjustable UCA. When I shift gears there is a pronounced slapping sound from the rear/center, around where the UCA bolts onto the frame. I checked the pinion angle after installing the UCA and it was within spec. Because I had never done it before, though, I took it to a trusted shop to double-check and to make sure I had torqued everything to spec. The sound is literally like someone slapping a butt--a big fat butt like mine. I suspect that something is actually hitting the underbody. First, has anyone else experienced this (the sound, not the butt slap)? Second, if something is hitting the frame how can I tell what it is when the car is moving? Finally, did I trust the shop more than I should have? IOW, should I take it somewhere else? Thanks in advance for your help.
  2. 07gts197

    07gts197 forum member

    First, this is in the wrong section.

    Second, do you have a video of this sound?

    Sent from my iPhone using Tapatalk
  3. Iceman62

    Iceman62 Bullitt 6005

    Get underneath the rear w/ creeper & check things out yourself...if this slapping's going on, there's got to be marks in the area(s) of origin.
    tbear853 likes this.
  4. wdrlaw

    wdrlaw Junior Member

    Sorry. Reposted in 2005+ forum. Old eyes.
    No, don't have a video.

    Great idea. Will look tomorrow. Thank you!
    Last edited by a moderator: Apr 8, 2021
  5. stkjock

    stkjock ---- Madmin ---- Staff Member Administrator Super Moderator S197 Team Member

    don't repost threads... moved.
  6. 07 Boss

    07 Boss Senior Member

    Have you ever replaced the bushing on the top of the diff, where the UCA bolts to?
  7. wdrlaw

    wdrlaw Junior Member

    Yes--Steeda UCA came with new bushings.

    @Iceman62: Spent about 20 minutes tonight under the car with a bright LED looking for scrapes, dents, scratches. Nothing other than evidence of very light contact with new jounce stops. The car is about 1-1/2" lower at all four corners--I can no longer fit the jack under it with a hockey puck, unless I drive it onto a 2x10. No visible scratches on diff/axle, UCA, stab or panhard bars, driveshaft, exhaust, or chassis/unibody.

    But I couldn't read what forum I originally posted in, so I might not have seen any marks.

    @stkjock: Sorry for reposting, won't happen again.
  8. stkjock

    stkjock ---- Madmin ---- Staff Member Administrator Super Moderator S197 Team Member

    This is a tech topic please keep on topic
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.