When I back up and turn at the same time, I hear a grinding/rubbing noise coming from the rear of the car. Anyone have the same problem???

 

That's strange, when I'm going forward while in gear (doesn't happen if I'm coasting in neutral) at low speed and turn at the same time, I hear an ugly noise that I'd also describe as grinding/rubbing. I'm not 100% sure if I have the same noise while in reverse, but I'll pay attention today and post about it later tonight. I'd be curious to know what it is, I'm thinking about taking it to the dealer although I'm not all that confident in their ability to diagnose and fix the problem, if there is one.

To give a description of the noise, it almost sounds as if the right front tire is rubbing up against something (but that clearly isn't the case as I only get the noise if I'm in gear).

Anybody else getting anything like this?

 

I can think of about four causes for grinding type noises on C6s. We ought to be able to come up with some simple troubleshooting steps to help people localize the cause of these noises when they get them.

1) For the rear end only (but do be sure it's the rear end - low frequency noises tend to amplify and transmit in ways that make them difficult to localize accurately. People get fooled) there have been issues with insufficient friction modifier additive, and also posi clutch paks. There may even be TSBs on these issues. If you are sure it is the rear, I'd check the faq, and/or search on those terms using the CF search.
http://forums.corvetteforum.com/show....php?t=1249546


2) Front end noises -- early in '05, there was a TSB relating to steering rack and pump. Did not hear of any later issues. [Edited to add link to steering hose recall - this looks like it was not related to noise, but to a complete failure -- not your issue]
http://www.automotive.com/2006/49/ch...lls/18801.html


3) Could be a tire rubbing on an inner fender that somehow came loose, or some other mechanical interference issue unique to your car.

4) By far, however, I believe most grinding noises while turning can be explained by a simple design factor -- high traction/fat tires, combined with steering geometry, on high traction surface, causes a very disturbing (but innocuous) vibration when at or near full steeering lock. If your noise only occurs (either backing or forward):

* At full steering lock
* From front
* Only when on high traction surface
* Happens once or twice per wheel revolution - is not continuous!

Then you have nothing to worry about, see attached link with explanation:
http://forums.corvetteforum.com/show...light=ackerman

 

Thanks Tracknoob. In my case, I doubt it's #4 (doesn't only happen at full steering lock), and I doubt it's #3 (it doesn't happen if I'm in neutral). My car is an '06 so it shouldn't be #2, either. I'm not 100% sure the sound is coming from the front but I think it is and I'll pay more attention tonight and tomorrow morning.

Incidentally, I noticed this noise not too long after I had it in to the dealership a few weeks ago to have my top checked and for an alignment. Do you think they could have done anything during the alignment that would cause this noise?

 

Here is some useful infor and a TSB that might solve the problem:

Rear Axle Chatter Shudder on Turns - keywords differential fluid noise oil #PIP3559 - (Sep 22, 2005)
Rear Axle Chatter Shudder on Turns
1999-2006 Chevrolet Corvette

2004-2006 Cadillac XLR

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Rear axle chatter or shudder on turns on Chevrolet Corvette and Cadillac XLR.

Recommendation/Instructions:
If this is the first complaint for this condition flush and fill the rear axle with P/N 89021669 (in Canada 89021670) gear lube and 4 ounces of the friction modifier additive P/N 01052358 (in Canada 992694).
If this is a repeat complaint or the condition persists after the flush and fill, replace the right and left rear axle clutch packs following published service procedures.
After clutch pack replacement use 1.6 l (1.69 qt) synthetic axle lubricant GM P/N 12378261 (Canadian P/N 10953455). and 4 ounces of the friction modifier additive P/N 01052358 (in Canada 992694).
Note: 2006 Z06 equipped vehicles require 2.55 l (2.70 qt) synthetic axle lubricant GM P/N 12378261 (Canadian P/N 10953455) and approximately 190 ml (6.4 oz) limited-slip differential lubricant additive GM P/N 1052358 (Canadian P/N 992694).

Note: Export vehicles use 2.01 l (2.12 qt) synthetic axle lubricant GM P/N 12378261 (Canadian P/N 10953455) and approximately 150 ml (5.1 oz) limited-slip differential lubricant additive GM P/N 1052358 (Canadian P/N 992694).

Once the axle fluid has been changed the car must be driven in 8 - 10 SLOW figure eights to work the fluid between the clutch plates.

Good Luck.
Bill

 

An no noise while not in gear. But only when turning.

So freaking weird, really worrying me.

 

The short version: Your positraction clutches are making the noise...sometimes telegraphs to sound like it's coming from the front of the car. There is a TSB out for this problem; they'll first change the fluid and add positraction additive...if that doesn't work, they change the clutch pack.

You say it doesn't make the noise in neutral, but you don't say if you are turning in neutral, or going in a straight line in neutral. The positraction clutch problem is primarily when you're turning...shouldn't matter if you are in neutral or not. If it goes away when you turn in neutral, it's something else...not the positraction problem.

Knowing the likely cause will only give you something to think about anyway...the technician is the one that needs to do the diagnosis.

 

I took it to the dealer today and tech took a ride and said sound is "normal". Said its' the rear end, relates to rear tires rotating at different speeds while turning. I will admit that my choice of words might not have been too accurate - "rubbing" is a better description than "grinding" (doesn't really sound like anything is "grinding"). It's very difficult to put a sound into words though, lol.

I started a separate thread to ask for feedback. Sorry for hijacking this thread seaya2, but I figured we might be experiencing the same thing (and indeed we still might be).

 

How is the replacement by the service tech going to be any better ? I'm not saying it dosen't need repair, but are they using different parts ? assembly technique ? something they could share with the assembly plant to prevent future problems ?

I'm no expert but IMO I think having it under a load a small load anyway, in gear will make a difference to the binding or whatever the problem with the clutch plates as compared to netural or out of gear.

The 8-10 slow figure eights to work the fluid after repair sounds like a good idea. Is this done at the factory during assembly ? Do they have another way to simulate this so it's not needed ? Maybe we should be doing this on a regular basis, at least for those of us (me included) who don't give it a real work out on the track ? Maybe those turns aren't sharp enough and we need to do a few donuts once in awhile.

Not to sound too negative, but the mechanical cause of why this is happening has me
Greg

 

Nobody is owning up to what went wrong at the factory (don't hold your breath either), but we have heard nothing here about a recurring problem with the clutch plates...once the problem is fixed properly, it's fixed.

The cause of the noise is the differential turning rate between the two rear wheels when you turn corners...the clutch plates have to slip relative to one another to allow this difference in turning rate, and the additive facilitates this relative slippage. If you don't have the additive, or enough of the additive, the clutch plates bind and grab causing the noise. Load would affect both sides of the differential the same...It's hard for me to see how you arrived at your opinion, but maybe you're right...WDIK.

Annnnnkkkkk! Your opinion above just dropped to, well, compromised. GM recommends you do the 8-10 figure eight turns to insure that fresh lubricant WITH ADDITIVE quickly works in between and across the surface of the plates (very likely brand new plates) to insure that the customer does not experience the noise again.

It would probably happen soon with normal driving, but the figure eights accelerate the process and allow them to insure the car is performing properly BEFORE it is turned over to the customer. Once this process is done, it never has to be done again...the lubricant is held between the plates by surface tension, and will quickly be replenished by normal driving.

Were the figue eights done at the factory?...JMHO...When pigs fly.

 

Talk about finding something when you need it!! My 2006 C6 auto started grinding in reverse but only when I was turning (backing out of driveway) but not when wheels were straight. The grinding (hear it and feel it) is only when car is first moving, can't duplicate it after I have been driving. When I got back after 20 miles of errands today, pulled in driveway, then backed out like I had at first, no noise. So...??

Why would it go away when warm? (And please use simple terms, I'm not a mechanic or gear junkie).

THANKS!

 

This is just a guess...long drive=hot differential fluid=lower fluid viscosity=reduced friction between clutch plates=no binding when clutch plates move relative to one another?

Take it in and ask them to check out the noise...you may have to leave it overnight so they can drive the car when the diff fluid is cold. They willl probably change the differential fluid under warranty in accordance with the TSB. It sounds like you may have some additive, but not enough to keep the plates from making noise when the fluid is cold.

 

Geez, I've got this problem too. I just hate the thought of taking it to a dealer, especially if they have to keep it overnight.

 

Some members have reported excellent service at a dealer in Austin...I can't remember the name; do an advanced search on "Austin service" or "Austin dealer".

Talk to the service manager, tell him you are not "keen" on leaving your car overnight. See if you can arrange to bring the car about 30 minutes before closing time and park it inside (that's about when they begin moving stuff around for closing), then show back up the next morning just as they are opening the doors and shaking out the cobwebs with coffee. (this means you'll have to take a day off)