Brian.Dainis

Hello,

I am new to this forum and this is my first post. I have a C6 2006 Corvette with the Z51 and paddle shift package. I think it has the A6 transmission in it. Not 100% if that is right or not though.

I discovered a few strange anomalies I wanted to mention to some seasoned pros. I do have an appointment with Tom Oates (A local Corvette Expert shop) for next week, but I want to be able to go in with a bit more knowledge on what Im dealing with.

So here is the things I am noticing and Im not sure if they are all related or not:

1) When foot is on brake and shift from Park to Reverse then into Drive there is a slight click noise coming from the rear end. It is actually kind of like a couple quick clicks together, not just one. And click might be the wrong way to describe it. It may be a click/creaking noise. But it happens every time I shift between Drive and Reverse. Not always between Park and Drive or Park and Reverse though.

2) This issue is very random and hard to replicate. From what I can tell in research it seems to be related to the rear differential fluid. But when I turn hard left or right when in drive or reverse, sometimes it makes a strange grinding noise. Almost sounds like a muffled version of what it would sound like to drag an empty filling cabinet across the pavement. Not sure if my analogy is helpful or not. It only happens at slow parking lot speeds as well. Never heard it while driving fast.

3) Lastly, I took it to the dealership for this issue about 4 or 5 months back and they said its fine and did some transmission computer update, but its still doing it. Anyway, when Im in manual paddle shift mode (Sport Mode) as Im de-accelerating, the car shifts back to 2nd and stops there, which is normal. But when I click down into first whether doing it from a slow roll or from a complete stop, the whole care jerks a bit and makes a slight sound. Kind of like something is engaging hard. The dealership test drove it twice and said its fine, but I feel I need to get that confirmed because it seems strange to me.

Has anybody had any issues like stated above and if so what was the outcome? Also does anybody think these are related or non-related issues?

PS. Go easy on me, this is my first post here. If I left something out just let me know and Ill do what I can to make sense of any questions or answers provided by the forum members.

Thanks!!!

V8ANGER

I think you have two separate issues. I also have the clicking issue you mention but mine is a M6. It happens when the clutch is engaged in either forward or reverse. I can hear it on the road too if driving next to a concrete barrier for the sound to echo off. This would be on the downshift. I've torn apart the suspension and put it back together thinking maybe it was something I never tightened when I changed out my axle. The noise went away but came back. Been launching from dead stops, drifting with no problems or without it getting worse. One day something will give and I'll find out what that noise was..hahahaha.

Your grinding noise sounds like your limited slip fighting with the pavement.

Your last one sounds like a good ol' this ain't no cadillac transmission in a sports car.

Brian.Dainis

V8ANGER, Thanks for getting back to me. I appreciate the information. As for the clicking noise, Ill keep you posted on Tuesday's outcome at the repair shop. Maybe it will be something you can use to solve your issue too.

For the grinding noise, Is that something that would fall under the common "changing the differential fluid" solution?

Also, for the jerk going from 1st to 2nd, thanks for clearing that up. Your the second person to tell me not to worry about it, so I can safely let that one clear my mind now.

And sweet drift by the way!!!!

V8ANGER

Thanks, that's just one that just happened to come out on camera being so dark up there. Go a GoPro now so I can capture better footage...

That would be awesome if the dealer found your problem with the clicking and everything else. I have yet to go under and tighten my rear carrier bolts as the dealer pulled it to get to my transmission.

You could change your differential fluid but I feel it's just the car has a good diff from the factory. I had a Kaaz two way diff in my other cars and a Corvette factory diff feels close to it. Not saying that it might be a problem though. How many miles do you have on your car? Upgraded parts?

Brian.Dainis

I want to get the GoPro too. I borrowed my buddies for some downhill mountain biking I was doing last year in upstate NY/NJ and I have been meaning to pick one up ever since.

Ill definitely keep you posted for sure.

It's all factory stuff on the car and it has just under 48K. It has seen the dealer its whole life for routine maintenance and any important TSB stuff that came out.

V8ANGER

Brian.Dainis

As a follow up:

I took the car out today and heard the noise quite a bit. I can't tell if its getting worst or if I am just noticing it more because Im listening for it. But I did hear it on a few occasions.

I think a better way to describe it now would be more of a slight knock sound. I also noticed it seems to make the sound while changing velocity. I notice it when accellerating or braking and also when making turns. It is definitly coming from the rear end. Also of course as the post states I notice it when shifting between reverse and drive while stopped.

It is kind of like a knocking mixed with the sound of a creak. Strange sound.

Im really hoping to get a definitive answer from the shop on Tuesday. Im not going to drive it again until then.

Knob Jockey

The grinding noise from the rear end is a common symptom related to the fluid.

If the car has been sitting idle for a length of time, you may need to just perform some tight figure eights, in reverse, to re-circulate the diff. fluid and friction modifier.

I have to do this every spring after my '06 A6 has been in winter hibernation.

Sorry I can't help on the clicking noises. However there is a relay controlling the back-up lights that may be audible when shifting in/out/thru reverse and the tranny is controlled by solenoids that can make a similar noise.

The paddle downshift from second to first while underway can produce a jerk depending on speed/rpm's. I'd call that issue 'normal'.

Glad you have a competent Corvette Shop that can service your car. Dealer repairs are quite often, a crap-shoot.

Congrats on the 'new' car and welcome to the Forum.

Chevy Cust Svc

Looking forward to the results from your shop visit on Tuesday, Brian.Dainis!

Sarah (Assisting Evan), Chevrolet Customer Service

Brian.Dainis

Follow up from Tuesdays shop visit.

I took it in. This is the shops response to all 3 of my concerns in order. Keep in mind this is the areas leading Corvette shop. They call themselves the Corvette doctors and have nothing but all year vettes and Camaro's in their lot.

1) It turns out it was actually two different things in the rear making the clicks. They put it on the lift with somebody inside the car to shift so I could see and hear it happen. The first click was coming from inside the transmission and they said its totally normal when its changing and moving gears for it to make a slight click from the trans. The second click was coming from the rear right axel. When shifting you could see and feel the whole thing jerk pretty badly. The left side is solid though. They ordered a new rear right axel for me and with parts + labor Im looking at a $995 bill. Not too bad I thought. I am kind of glad its not something worst.

2) The grinding I hear when making tight slow speed turns is most likely related to the differential fluid. They had to order a part for the 1st problem and when I go back to get it installed they will do a fluid change as well. They said there is an additive to include in it and this is almost guaranteed to solve the grinding noise. They said it has to do with the wheel slip. They stated it sounds bad when its grinding but its really not something to worry about. Just to do the fluid change and Im good. They stated it should be done around 40K - 50K miles and thats where Im at with mine.

3) They said the car should jerk going from 2nd to 1st. There is a ton of power to the wheels and the trans is doing some serious work at that gear. Its normal.

V8ANGER

The axle huh...interesting!

Brian.Dainis

Yeah.... I was kinda shocked too. The tech at the shop took me back and showed me what he was talking about. I had my hand on the piece that connects the rear right axel to the wheel. The whole thing jerked when the gear was shifted. Now that its getting cold here its getting even louder. Im just putting the car away until they get the part and are ready to do the swap.

V8ANGER

When I was diagnosing my sound I had a feeling it was the axle too. I had broken the other axle on the other side and replaced it when this noise came out of nowhere. Perhaps I better pickup another axle as well in preparation of this one breaking too. I'll pull it out one day to see if it makes the noise out of the hub and diff on it's own. Perhaps the CV joint has gone bad or on of the bearings smashed...we'll just have to see....thanks for your post.

Brian.Dainis

I just got back from the shop with the new right rear axel in place. The sound is completely gone. I now only hear a very faint sound when going from reverse to drive and it does not sound like a bad sound at all. The shop said it is completely normal to hear that sound.

But the bad sound I was hearing before was definitely from the axel.

They also did diff fluid and said it came out pink and is not the normal recommended fluid. So they added new diff fluid and the additive to go with it.

No more ugly sounds coming from the rear.

V8ANGER, if you can get your vette on a lift with somebody in it to shift gears you may be able to see your axel to wheel connection making the sound as well. Just a thought. Let me know if you get yours solved too.

Thanks everybody for your help.

V8ANGER

Glad you got yours fixed, I'll probably end up waiting till it breaks. No sense wasting a axle! Hahahaha. Thanks for your posts though good info!

Brian.Dainis

It seems like your a bit more hands on with your vette which is cool. I will leave it to the pro's when there's a problem. Im not much of a mechanic.

Keep me posted if there is any updates on yours however. Im interested to know now that the discussion has been started.

V8ANGER

Will do that. Hopefully get a few more miles on this axle.

c6miller

You may want to change the differential fluid and check the axel nuts . these are inexpensive items that should be checked anyway.

V8ANGER

Haven't checked the diff fluid yet but axle nuts been checked. Thinking about going with Royal Purple in the diff.

goshendad

I had clicking in my 2009 z51 when going in 1st or reverse. Ended up being loose axle nuts. Quick fix.

I am new to this forum and this is my first post. I have a C6 2006 Corvette with the Z51 and paddle shift package. I think it has the A6 transmission in it. Not 100% if that is right or not though.

I discovered a few strange anomalies I wanted to mention to some seasoned pros. I do have an appointment with Tom Oates (A local Corvette Expert shop) for next week, but I want to be able to go in with a bit more knowledge on what Im dealing with.

So here is the things I am noticing and Im not sure if they are all related or not:

1) When foot is on brake and shift from Park to Reverse then into Drive there is a slight click noise coming from the rear end. It is actually kind of like a couple quick clicks together, not just one. And click might be the wrong way to describe it. It may be a click/creaking noise. But it happens every time I shift between Drive and Reverse. Not always between Park and Drive or Park and Reverse though.

2) This issue is very random and hard to replicate. From what I can tell in research it seems to be related to the rear differential fluid. But when I turn hard left or right when in drive or reverse, sometimes it makes a strange grinding noise. Almost sounds like a muffled version of what it would sound like to drag an empty filling cabinet across the pavement. Not sure if my analogy is helpful or not. It only happens at slow parking lot speeds as well. Never heard it while driving fast.

3) Lastly, I took it to the dealership for this issue about 4 or 5 months back and they said its fine and did some transmission computer update, but its still doing it. Anyway, when Im in manual paddle shift mode (Sport Mode) as Im de-accelerating, the car shifts back to 2nd and stops there, which is normal. But when I click down into first whether doing it from a slow roll or from a complete stop, the whole care jerks a bit and makes a slight sound. Kind of like something is engaging hard. The dealership test drove it twice and said its fine, but I feel I need to get that confirmed because it seems strange to me.

Has anybody had any issues like stated above and if so what was the outcome? Also does anybody think these are related or non-related issues?

PS. Go easy on me, this is my first post here. If I left something out just let me know and Ill do what I can to make sense of any questions or answers provided by the forum members.

Thanks!!![/QUOTE]