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Rear-end Knocking Noise

Joshdc

By Joshdc,
in South Australia

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Joshdc Enthusiast

Joshdc

Posted
Posted (edited)

Driving home from work tonight, the GTR started making a noise I havent heard before. From inside it sounds to be coming from the rear of the car like the exhaust is slightly bouncing up and down knocking into the metal frame. It only occurs while decelerating but its repetition is timed with the speed of the car so the faster I'm going the more often the noise goes. Almost like something builds up momentum and bounces up and down. It may also occur over bumps but the R33 is so loud I cant quite tell (and my hearing is subject to the placebo effect). The noise does not occur while accelerating or under brakes, gears and clutch position were irrelevant.

I jacked it up and started wobbling things trying to work it out but haven't found anything obvious enough to trigger my limited mechanical skills. Looked in the wheel arches for anything rubbing or stuck to the wheels but no. Checked all fluids levels were ok, nothing leaking (except airconditioning condensation), no eccesive knocking showing on the powerfc...

It's loud enough to concern me, I'm sure people driving next to me can hear it.

Any ideas?

Edited by Joshdc
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https://www.sau.com.au/forums/topic/294230-rear-end-knocking-noise/
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Dohmar Grand Master

Dohmar

Posted
Posted
Driving home from work tonight, the GTR started making a noise I havent heard before. From inside it sounds to be coming from the rear of the car like the exhaust is slightly bouncing up and down knocking into the metal frame. It only occurs while decelerating but its repetition is timed with the speed of the car so the faster I'm going the more often the noise goes. Almost like something builds up momentum and bounces up and down. It may also occur over bumps but the R33 is so loud I cant quite tell (and my hearing is subject to the placebo effect). The noise does not occur while accelerating or under brakes, gears and clutch position were irrelevant.

I jacked it up and started wobbling things trying to work it out but haven't found anything obvious enough to trigger my limited mechanical skills. Looked in the wheel arches for anything rubbing or stuck to the wheels but no. Checked all fluids levels were ok, nothing leaking (except airconditioning condensation), no eccesive knocking showing on the powerfc...

It's loud enough to concern me, I'm sure people driving next to me can hear it.

Any ideas?

do you have adjustable rear upper control arms? mine are noisy compared to the stock bushs+control arm

-D

Joshdc Enthusiast

Joshdc

Posted
  • Author
Posted
do you have adjustable rear upper control arms? mine are noisy compared to the stock bushs+control arm

-D

Stock arms as far as I know, the bushs arent stock, but that was changed wtih the suspension a few months ago and hasnt made the noise before.

MYCEF3 Collaborator

MYCEF3

Posted
Posted (edited)

I was thinking Diff as well!!!

Happened the the cef one day, was driving on one day n the diff was noisy! and then it got noisier then it went bang as i was doin a Ubolt! after had really loud bangs on excleration and deceleration the faster i went the quicker the bangs! Checked it out as i crawled home (everyone stareing) And found the diff was f**ked. Had to go out n buy a new diff

1.5 way LSD :P

Edited by MYCEF3
MYCEF3 Collaborator

MYCEF3

Posted
Posted (edited)

Yeah same i hope it isnt the diff as well!

If its youv looked at all the exhaust, coilies and other stuff that could knock or hit, the other is the diff (only coz the banging ur hearing)

Edited by MYCEF3
  • 5 months later...
Joshdc Enthusiast

Joshdc

Posted
  • Author
Posted

Woops I forgot to post the resolution.

Luckily I found the source before I lost a wheel...

Turns out i am an idiot and didnt tighten a couple of wheel nuts properly. Caused this noise for a good week of driving - all good now though.

Thanks every for the suggestions.

:)

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