Loud bang in rear end

Discussion in '2011+ Mustang GT 5.0L Tech' started by Stage 3 Proto, Aug 18, 2019.

  1. Stage 3 Proto

    Stage 3 Proto Junior Member

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    Need help. Is anyone else experiencing a very loud banging noise from the rear end when shifting under acceleration into second gear? If this has happened, you will certainly know it, it's extremely loud and alarming.

    I have already replaced the drive shaft with a one piece Ford Racing aluminum drive shaft, new twin disc clutch, new universal joints, new BMR upper control arm and bushings.

    Any help would be appreciated!
     
  2. 01yellerCobra

    01yellerCobra forum member

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    What about lower control arms? Did you check the clearance between the exhaust and axle?
     
  3. Stage 3 Proto

    Stage 3 Proto Junior Member

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    Plenty of clearance . This is a very loud bang that only happens under extreme acceleration. I suspect it might be in the differential .
     
  4. Stage 3 Proto

    Stage 3 Proto Junior Member

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    Does anyone know if my 8.8 differential could be the cause of a loud bang under hard acceleration ? It's a 2011 Roush stage 3
     
  5. stkjock

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

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    have you checked for slop in the drive train
     
  6. nbk13nw

    nbk13nw forum member

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    Could be a loose fastener in the rear upper control arm as well. Mine made a noise after a few weeks due to replacing the rear upper arm. I found that one fastener had worked loose.
     
  7. 1950StangJump$

    1950StangJump$ forum member

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    Perhaps a little more info would help . . . is the bang when you engage the clutch and shock the drivetrain, or is it when you actually change from 1st to 2nd and before releasing the clutch pedal?
     
  8. eighty6gt

    eighty6gt forum member

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    I have this, turns out it was this vegan chili I had eaten earlier!
     
  9. Mrerob

    Mrerob Member

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    I had that happen and it was the adjusting but on my upper control arm worked loose
     
    Stage 3 Proto likes this.
  10. Pentalab

    Pentalab forum member

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    Check the bushing at the differential end of the uca. If it's trashed, replace with another oem rubber bushing....or steeda spherical. Don't replace differential end of uca with the bmr poly. Even bmr will tell u, u can't use a poly to poly uca setup..... the uca won't rotate on it's axis. At least one end of the uca has to be able to articulate.

    A go pro camera under there will tell you if stuff is hitting. Your oem lsd could also be trashed.
     
  11. Stage 3 Proto

    Stage 3 Proto Junior Member

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    Thanks for all the replies. I should have been more clear on the loud bang. It is not shifting related . it happens when there is extreme torque on the drive train . usually in 2nd gear at 4K to 6k RPMs . Everything from the trans on back to the differential has been replaced. (driveshaft. U-joints BMR upper control arm! I really like the Idea of mounting a go pro under the car to see what is going on! Can you tell me what the lsd that you referred to is?
     
  12. stkjock

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

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    LSD - limited slip differential

    since you replaced everything in the trans back, did you check all the bolts since?
     
  13. jewc75

    jewc75 Cant Stop, Wont Stop

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    Did you replace the uca mount?
     
  14. Stage 3 Proto

    Stage 3 Proto Junior Member

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    Yes, I took the BMR control arm off and put locktite on the adjustment threads and re-tightened everything !
     
  15. jewc75

    jewc75 Cant Stop, Wont Stop

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    Did you torque the bolts or just tighten?
     
  16. Stage 3 Proto

    Stage 3 Proto Junior Member

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    Yes, The stock UCA was beefed up at Roush when the car was lowered but they used the factory mount. I replaced that mount with the heavy duty BMR mount. I torqued the big bolt thru the trunk to 200 ft.lbs. and the other two under the car to 150 ft.lbs.
     
    jewc75 likes this.
  17. Stage 3 Proto

    Stage 3 Proto Junior Member

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    The noise happened with both mounts
     
  18. Pentalab

    Pentalab forum member

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    Check the differential end of the uca. If trashed, it will flop around like crazy. (go pro vid will make u gag).

    I had my 2010 lowered at Roush dealer...... which resulted in oem LCA's being higher at axle ends. Bad wheel hop, lousy traction, dangerous in the wet...and real hard on oem rubber uca bushing at axle end. In went the BMR HD boxed LCA's (poly at both ends). + BMR lca relocate brackets, (use middle holes) plus BMR adjustable poly UCA + BMR uca mount. BMR lca's now lower at axle ends. No more wheel hop, I got my traction back. At the time, I also installed the BMR adjustable PHB and mating PHB brace.

    2 years later, I replaced the oem LSD with an eaton tru-trac...and replaced the adj PHB + brace...with a whiteline watts link... + DSS-DS + bmr rear tunnel brace + mating bmr rear safety loop.
     
  19. Stage 3 Proto

    Stage 3 Proto Junior Member

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    Thanks. I just bought the factory bushing for the differential UCA It's the only thing left !