# knock, clunk sound from rear!



## Str8evl (Feb 13, 2008)

Hey guys,

I know I probably should have searched more about this problem before posting but here it goes.

I have almost 43000 miles on my GTO and I drove the car across country from California to North Carolina and I have started to definitely a knock or clunk from the rear when I let off of the gas pedal. I have no idea what could have caused this I never and I mean never tear on the car. I have an extended warranty with Hendrick Automotive and was thinking that should take it in. I don't know if the rear end is going bad or one of the half shafts could be breaking. 

It only makes the noise letting off the accelerator and when its in 1-4 gear, not so much in 5th of 6th. Any help would be greatly appreciated. I hate thinking that something could be wrong with the car.

Thanks in advance.

John


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## GTO JUDGE (May 14, 2005)

Mine did the similar thing especially when starting out, growling, clunking, and some knocking. The rear end gear oil was changed out and refilled with synthetics and friction modifier. Problem was solved. Could be your oil is breaking down? Was the gear oil ever changed? 

http://www.gtoforum.com/f3/growling-clunking-noise-coming-rear-14102/


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## Str8evl (Feb 13, 2008)

I have not done it yet, but making an appointment tomorrow. Thanks


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## taz4141 (Nov 6, 2006)

What is a Carrier, Limited Slip, Locker and Spool?

Limited Slip Differential - Wikicars

HowStuffWorks "Clutch-type Limited Slip Differential"

we had a discussion on this in another thread and i found these website to go visit there's much more info out there but, this is a good place to start. most folk's do not know little things that cost big money,i guess that's why we all talk here. to learn and listen. Ive learned a lot for some really talented folks on the forum.

GTO judge know a lot of facts. gm4life has great experiences. each user has something to bring to the table,in one way or another. there are some folks that love the car for what it is ,and the rest of us, built the crap out of them, ether way you should get some good help here.


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## GM4life (Mar 18, 2007)

I had the exact same problem as you had with GTO JUDGE's thrown in the mix also. I changed the fluid three times with three differant fluids and limited slip additive, it still did the same thing after it warmed up. Eventuly I took it to the dealer had it replaced, bad carrier. Thank god it was still under warranty. Do what JUDGE did first and see will that help you. GM has a new rear end fluid now that suspose to be better, because folks with C5 and C6 Z06 was having problems too. If that doesn't help you push to get your diff changed.


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