Scraping/Grinding Noise?
Thread Starter
Melting Slicks
Joined: Oct 2001
Posts: 2,786
Likes: 49
From: Sun Devil Country
Scraping/Grinding Noise?
Took my 99 A4 coupe into the dealer previously for a scraping/grinding noise coming from the rear (almost sounds like the right side, but can't pinpoint it)when making a right or left 90-180 degree turn at 5-10 mph. They tried lubing the rear brake calipers-no effect, R&R'd the rear bearing packs-no effect, and R&R'd the left differential seal near the boot (due to a leak) and the differential grease/limited slip additive-that seemed to fix the problem. That was about a month ago and now the sound is back intermittantly just like before. :mad Its pretty much a given that they R&R'd the differential grease/additive with a GM call out. I know some of you guys said switching to Redline or Amsoil makes a difference in the differential and transmission, but it's kinda of hard to believe that the lubricant the dealer is using is causing the problem. Can anyone help me out? :cry
Burning Brakes
Joined: Nov 1999
Posts: 805
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From: Newport Coast, CA USA
Re: Scraping/Grinding Noise? (Bandit1)
I had a similar problem on my '99. However, I do not know if the source is the same. I went round and round because the dealer could not duplicate the problem, as it was an intermittent thing. I discovered that if I drove the car close to a wall or building, the sound was much more apparent. Finally, the dealer heard it. It turned out that I had a bolt missing from a caliper. You might try the technique of driving near a wall to isolate the sound.
Former Vendor
Joined: Apr 2001
Posts: 10,976
Likes: 21
From: FL
St. Jude Donor '13
Starting in 1999,GM switched to synthetic for rear end lube.In many cases,the additive seperates (states it on the bottle) from the synthetic causing the posi clutch plate groan noise from the diff...In some cases,this is aggravated by varnish build up on the clutch plates that is impossible to remove short of dissassebly,unlike a conventional rear were you could remove the cover and spray a cleaner on the plates...Of course,if you change the fluid,the noise will go away,but the potential is there that it will return such as in your case (usually 3-5000 miles)...
You can change the fluid to GM #12345977 plus the additive (as per GM) and the noise shouldnt return.I have done this many times with positive results :yesnod:
You can change the fluid to GM #12345977 plus the additive (as per GM) and the noise shouldnt return.I have done this many times with positive results :yesnod:
Drifting
Joined: Aug 2000
Posts: 1,253
Likes: 3
From: Chapel Hill NC
Re: Scraping/Grinding Noise? (Bandit1)
I haven't heard of anyone else but me having this problem but my right rear brake rotor sometimes contacts the end of the lower A-arm under hard left-hand cornering and makes a grinding noise which took me a while to figure out. Good luck.
~Cass
~Cass
Pro
Joined: May 2000
Posts: 693
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From: Merrick NY
Re: (C-5 TECH)
C-5 TECH
I think this is the sound that is coming out of my rear too. I hear the same groaning noise whether going forward or reverse. Do you think it's the same thing? I started to hear this noise about 3 weeks ago. Mine is a 2000 with about 27k miles. Never had the rear end fluid changed yet. Is this sound bad or a premonition of worst things to come, or is it just a thing that makes noises but has no harm like the "marbles in the can" noise with the tranny.
I think this is the sound that is coming out of my rear too. I hear the same groaning noise whether going forward or reverse. Do you think it's the same thing? I started to hear this noise about 3 weeks ago. Mine is a 2000 with about 27k miles. Never had the rear end fluid changed yet. Is this sound bad or a premonition of worst things to come, or is it just a thing that makes noises but has no harm like the "marbles in the can" noise with the tranny.
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Former Vendor
Joined: Apr 2001
Posts: 10,976
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From: FL
St. Jude Donor '13
It is quite common,so you are most likely dealing with the same issue.Of the 60 or so cases that I have addressed,simply switching to the fluid I posted earlier did the trick.On 2 occassions,I had vehicles were the noise returned.After dissassembling those 2 rear differentials,excessive varnish build up was evident on the clutch packs,with absolutely no wear to the clutch material surface.Replacing the clutch packs cured those 2 vehicles...In other words,it is not a durability issue if addressed in a timely manner,just annoying ;)
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Re: (C-5 TECH)
C-5 TECH,
That's another golden nugget of knowledge! Thanks again for posting here! It's greatly appreciated :D
That's another golden nugget of knowledge! Thanks again for posting here! It's greatly appreciated :D
