wierd noise
Thread Starter
Teching In
Joined: Oct 2004
Posts: 5
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wierd noise hey guys i just bought a 99 z28 with the 4 speed auto and during declerating its got a wierd noise almost the noise you hear when a cv joint is going in a fwd now when i turn it gets louder it kinda sounds like a rear end. I talked to a guy here in utah says its really common in camaro's. Now it doesnt do it under acceleration. One other thing i noticed if i put it in first gear or 2nd gear get on it to get the rpm's up and let off it acts like it has a clutch and idles at 600 tell i touch the gas then it will go back up to the rpms unless i do not touch the gas again. Any ideas what is going on or if thats normal?
On The Tree
Joined: Oct 2004
Posts: 109
Likes: 0
From: Yorktown, NY
I have the same problem with the noise slowing down, and i talked to my auto teachers, and they said my rear is going, but i talked to another FBody guy, and he said its normal. My car is under warranty, so if it goes, i get a new one anyway... Thats basically how im looking at it now
i'm having the same problem coming from the rear. its a rattling noise that will rattle fast or slow depending on how fast the wheels are turning and only when i'm coasting. i notice it more when i'm coasting in a turn. i took it to the dealer yesterday, so hopefully i will find the answer soon. i've heard that it could be the u-joint or broken mount but who knows. but hey if its the entire rear end i'll go and buy a stronger one which i want to in the future anyway. 01 z28 m6 with 33,000 miles by the way.
well the guy at the dealer didnt hear the noise when he drove it so he said i'll have to bring the car in during the day so i can point it out. i really payed attention to it yesterday when i got the car back and it really is just when i'm in a turn or curve. the harder the turn the louder the sound and the faster your wheels are turning the faster the rattle.
Staging Lane
Joined: Apr 2004
Posts: 93
Likes: 0
From: kenosha, WI
My car has the same problem as you all do. Mine makes noise on decel and only making left hand turns but once throttle is applied it stops. Took to a local dealer cause a friend works there and he looked at the car. He had no idea what it was asked around the shop neven made some phone calls. He told me don,t know how true it is because i don't know alot about diffs but he said that because it is a coned type of diff it is more likely to make that type of noise. I don't how true that is if the diffs are a cone style of operation or if it would be like clutch packs. i really need to learn a little more about that but this is the explanation he gave so I will just live it till it 
and buy a 12 bolt. Hope this helps a little cause I don't understand it myself.
and buy a 12 bolt. Hope this helps a little cause I don't understand it myself. Trending Topics
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TECH Senior Member
Joined: Apr 2004
Posts: 6,157
Likes: 1
From: Texas
Originally Posted by 105
well the guy at the dealer didnt hear the noise when he drove it so he said i'll have to bring the car in during the day so i can point it out. i really payed attention to it yesterday when i got the car back and it really is just when i'm in a turn or curve. the harder the turn the louder the sound and the faster your wheels are turning the faster the rattle.
What I was suggesting is dumping the clutch a few times to help the problem out
. As long as you have warranty left why not. Its better then it breaking on your pocket. i already check the warranty on this car and it expired in early 2004 before i got the car, otherwise a great idea. i was wondering if something could just be tightened up back there. wheel bearing???
Teching In
Joined: Jun 2004
Posts: 3
Likes: 0
From: West Chester, Pa
Originally Posted by racecarr
My car has the same problem as you all do. Mine makes noise on decel and only making left hand turns but once throttle is applied it stops. Took to a local dealer cause a friend works there and he looked at the car. He had no idea what it was asked around the shop neven made some phone calls. He told me don,t know how true it is because i don't know alot about diffs but he said that because it is a coned type of diff it is more likely to make that type of noise. I don't how true that is if the diffs are a cone style of operation or if it would be like clutch packs. i really need to learn a little more about that but this is the explanation he gave so I will just live it till it and buy a 12 bolt. Hope this helps a little cause I don't understand it myself.
and buy a 12 bolt. Hope this helps a little cause I don't understand it myself.I also have this EXACT same problem...left turns and all. I got ahold of a list of the Technical Service Bulletins yesterday and found that there is one for "rear brake rattle". I don't have the number here with me at work, but I'm wondering if anyone has access to pdf's of some of the bulletins? I have had rear wheels off and tried to physically shake things like suspension, brakes..etc..etc.. but no luck duplicating the noise in the garage. Anyone else???
i talked to some guys at z28.com and one guy said he had the same problem with rattling coming from the rear as i described and he said when he replaced his lower control arms and panhard bar the rattle was gone. he noticed that the bushings were all rusted and torn up on the old parts. i think this is the answer. its worth getting aftermarket lca's and panhard bar anyway. i guess you could just get new bushings though. also another guy said to reduce noise coming from the actuall rear differential you can get some posi lube from gm. you have to add it to your differential fluid when you change it out. hope this helps. let me know if you fix the problem before i do!
Originally Posted by 2MuchRiceMakesMeSick
Sorry man, all I can tell you at this point is to start saving your money. The rear is the weakest link on our cars....
Teching In
Joined: Apr 2005
Posts: 8
Likes: 0
From: Mass
This thread has been dead for a while. Did anyone find a resolution of this issue. It is exactly what I am experiencing. I had the rear end rebuilt and that solved the high pitched whine at high speeds but not the slow speed clunk... clunk... clunk that is described in this thread. I also took one of the control arms down and inspected the bushings and they looked fine! I just changed the gear oil in the rear end to make sure that there were no metal shavings and filled it with Valvoline gear oil that has the GM addative in it. Is that oil alright to use or could that be adding to my problem? What else can I look for...? I heard in another thread that there was a TSB about a rattle in the rear brakes, any one heard of that?