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Discussion Starter #1
So my car, which I bought new in late 2013, just had service light come on that seat "Rear Axle System off" during normal operation. The car seemed to drive fine with no noticeable change in spirited driving or in tight corners. There was no whining, clunking, wheel slip, or any other indication there was a problem. So I took it to the dealer anyway and when I got it back their paperwork read,

"Found code C0413, inspected and found a lot of metal in the rear differential. Recommend replacing rear differential assembly. $4106.12".

After talking with the service representative, they said the part was backordered, so we had them put some new oil in and we drove it off. The "Rear Axle System Off" warning comes on about half the time, usually after the car has been sitting for a few hours or overnight. It still drives perfectly fine though. Seems crazy to spend over $4k to fix something that has no real symptoms. They said the part alone was about $2700. I asked for a price breakdown with the part numbers to see if I could find a used part instead.

I asked them to print the service history, and sure enough in late 2013 it looks like they checked the differential fluid level, found it low, and filled it up. The car was only a few months old at that point and had about 4000 miles on it. Since we never had any issues, we didn't think anything of it.

What do you guys think I should do? Replace it, leave it, find a used part? What is the failure mode if it doesn't get fixed?

Thanks for your help
 

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Im assuming that is not covered under the drive train warranty?
Wow big ticket repair for sure.
If you're out of warranty i would check around for a good independent Corvette shop for a quote.

Sent from my SM-G955U using Tapatalk
 

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Discussion Starter #3
I assume there's no more drive train warranty. The car was bought in September of 2013, so more than 5 years ago. I don't know of any extensions for this part.
 

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In and of itself, a service technician writing that he "found a lot of metal in the rear differential" wouldn't mean anything to me.

I found a "lot" of metal in my rear differential fluid when I changed it at 4,726 miles. What is a "lot"? It is whatever I define it to be. It is whatever you define it to be. It is whatever the service technician defines it to be. In my opinion, such a statement is meaningless.

Of course, it is your car, and you should do whatever you wish. If it were my car, I would change the rear differential fluid myself. These links could be helpful if you decide to do that:
https://www.stingrayforums.com/forum/general-discussion/76121-rear-diff-oil.html
https://www.stingrayforums.com/forum/general-discussion/27513-2016-z06-low-rear-differential-fluid.html

Next, I would try to find out why the "Rear Axle System off" light came on. Is it really the rear differential? Is it just a battery problem (that has been reported as causing such a message to other people). Is it something else?

If I were you, I would take it one step at a time, as above. Of course, you are not me, so you need to do what makes you feel comfortable.
 

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Welcome to the C7 world. I have a friend that had his replaced under warranty, and I lost mine on the racetrack. The regional rep in cahoots with the dealer denied the repair as I was on the track. I showed them the manual where it tells me how to prepare my car FOR THE TRACK. I showed them that the Z51 is the TRACK PACKAGE! I proved to them that this wasn't competitive racing. Still no go. So I sent an email to three VPs in Detroit, and eventually after me paying for the repair and four months of hassle, the dealer was forced to write me a check for the repair, with was about $5,500.
I bought an extended warranty BTW just before the original one expired. I think it's 7 years and $80,000 miles. Initially a dealer wanted $3,000, but I talked him down by playing the field to $1700.
 

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Go back to your dealer and have them update the calibrations for the rear drive module, I have seen many with this intermittent concern. You need to find a dealer with a Corvette certified tech if they can't prove they are then go somewhere else. I am one. While they have the GDS system connected, go ahead and update all the modules the new calibrations greatly improves vehicle overall operation, what dtc was stored?
 

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Go back to your dealer and have them update the calibrations for the rear drive module, I have seen many with this intermittent concern. You need to find a dealer with a Corvette certified tech if they can't prove they are then go somewhere else. I am one. While they have the GDS system connected, go ahead and update all the modules the new calibrations greatly improves vehicle overall operation, what dtc was stored?
Are you at Holiday Chevrolet Cadillac? One of these days, I will probably need a good dealership to go to, and it is too far to go back to Fremont Chevrolet in California where I used to get excellent service before I moved to North Carolina.
 

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sorry to hear about your troubles with the e-diff. The stories of GM backing out of their warranty seem to be far too common in an increasingly complex automotive world. Its a shame they automatically seem to deny anything and everything powertrain related. If it drives fine and has fresh fluid, I would just drive it if there does not seem to be any other adverse effects.

Question: how old is your battery? Reason I ask, I have a buddy with a '16 Z06 with a ton of mods...he kept getting a 'service rear axle' warning but it seemed to come on intermittently, with no noticeable performance difference. The shop he took his car to for all the performance mods couldnt replicate the issues, as the diff seemed to be working well. Turns out his battery was old and the ground/power cables were loose, which was causing (I think) voltage irregularities which the E-diff didnt seem to like too much.

in anycase, hopefully everything works out for you. check your battery cables!
 

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Discussion Starter #9 (Edited)
Just wanted to post a happy update.

The dealer got GM to replace the e-diff at no cost to me. Because we had a service record of the dealership filling the diff oil after the recall/TSB back in 2014, the dealer argued that the damage to the diff occurred while the oil level was low. As a result, they believed damage was done while the vehicle was under warranty. GM agreed and is covering the cost.

It's worth noting that we've had the car for almost 6 years (delivered September/Octover of 2013) so it's definitely beyond the bumper to bumper and powertrain warranty.

Your mileage may vary, but it's definitely worth asking for support from the dealership or factory if anybody ever has a similar issue.

Dealership is MacMulkin Chevrolet in Nashua, NH. While it's GM and not them that are covering the cost, they really went out of their way for me to contact GM and convince them to cover it, so I think it's fair to give them a shout out.



Also:
I appreciate everyone's advice about the battery and the code clearing, etc, but since they found a bunch of metal in the differential oil when they changed it, I think there was actually some physical damage to it. I never saw the oil myself, but I trust that the technician wouldn't just make that up.
 
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