eLSD Problem?
 

1 day short of having my C7 Z51 for a month a problem has developed. This afternoon I got the dreaded "Service Rear Axle" message in the display. Having read other posts I know that in some cases this could be a minor issue so I continued driving towards my home less than 10 miles away.

As I continued the rear end noise started getting louder and making a "thumping" sound as if I had a flat tire. I checked the tires and they were still good with the proper tire pressure as well. I continued on and decided to switch it from Sport mode to Touring mode to tone down the exhaust sound a little so I could better listen to the sounds coming from the rear end. When I switched it to touring mode there was a pretty pronounced "Clank' sound. When pulling into my garage I got out of the car and immediately there was a strong smell of burnt rubber. A visual inspection under the rear didn't show any signs of wear or leaking fluids.

I called my local dealer and they told me to have it towed to them first thing Monday morning. I have read other post where the Z51 eLSD has been having a few issues. I made sure my dealer checked the fluid in the rear diff when I picked it up last month so I don't think its related to that issue. I only have just over 750 miles on it. VIN# 4629

Did you ever have the differential lubricant level checked before this?

Yes. When I took delivery on 11/1 from one of the major forum dealers I asked several times and was told that they were aware of the bulletin and they check all their cars as part of the PDI. I also haven't noticed a single drop of any fluids on the garage floor under my Vette.

From reading posts from users with similar symptoms it almost seems the eLSD controller was flaking out causing the wheels on each side to become out of sync or something. I'm no mechanic though but that would explain the burnt rubber smell. I will follow up once the service dept determines the root cause.

Hope it's a simple fix :cheers:

Don't worry too much. Warranty will take care of any major issues if any. I think it's better to have problems right off the bat than just when your warranty had run out.

Happened to me with my 2011 C6 Base Coupe. Steering issues, some oil leaks...
All taken care of by the dealer under warranty. I loved that car, but, I traded her for my C7. I miss her so. If I could keep her, I would have.

Sorry to hear that irpete. My VIN is very close (4709) and literally hit the 1,000 mile mark today, so I will be watching this thread closely. Good luck and thanks for posting.

Please keep us updated about your eLSD problem.

I know GM will make it right and If it was going to happen I'd rather it happen under warranty. I will post updates as I get them.

Why don't you post this in the sticky thread at the top. Kelly from GM monitors that. I'd just copy and paste your original post.

Good that it's going to the dealer on a flatbed. If it turns out to be a lubricant issue then you now the dealer just 'thought' his mech checked it. I watched them check mine by dipping a wire into it. The plug is in the top and you just have to remove it and stick something long enough down to make sure lube is there. And there isn't much room to work in.

What was the last four of your vin? Mine was 3206, I think it was out of the danger #'s.

***Update***

Car was towed to my local dealer this morning after getting the "service rear axle" warning. I just got a call and it appears that this was in fact a lubricant issue. My local Service manager says that the bulletin that went out 4 days after I picked up my car and it lists my VIN# as in the range of cars that need to be checked. They will now have to replace the entire rear end.

The sad part is that I specifically mentioned to the dealer that I read on the forum that several cars were found to have little or no rear diff fluid in them and I was assured that they check this as part of the PDI.

I would have thought that if my VIN #4629 was in the problem range on a bulletin someone would have notified me to have my car checked out.

Prior to the "service rear axle" warning there weren't any signs of a problem in the 700 miles I've put on it so far. Once I got the warning I drove straight home (less than 10 miles). So if your VIN is anywhere near the range of #4629 you may want to have yours checked.

From what has been reported on here, most of these problems require a re flash of the computer. Not a replacement.

Maybe ask the dealer to try that first. Do a search on here to see the people that this helped.

I asked. They said there was barely any fluid in the rear diff and driving it with little fluid has destroyed the rear end. Trust me, I'd rather have them replace the rear diff than to just add more fluid and re flash.

Just to clarify:
It would seem that most of the issues reported, are regarding the rear AXLE, not the eLSD being low on fluid and hence getting fubar'd.
Was that the case with your vehicle?
The fact that people don't know a whole lot about the new rear end yet, leads to the eLSD getting a bad rap around here, for what seems an axle issue...

Good point. The reason I started it as a potential eLSD problem is because I was assured by my dealer that they were aware of the low fluid problems and that they check it as part of PDI. Sorry for any confusion.

No need to be sorry. :)
I just try to avoid confusion.

What I heard was that there was a batch of bad production boards that went out - bad meaning either firmware or hardware. According to my sources, this is the real reason behind Z51 constraint.

It really appears there may be 2 separate problems: mechanical issues and controller issues. Hope they can get this sorted out quickly.

After reading through this thread and a couple of others, I gave my dealer a call for more information. What I learned is that there is an open "recall" on my car, VIN #2708, to check the rear diff fluid level. I asked if it was a recall or bulletin. I was told it's a recall.

I'm in the ATL area and the first diff that was low/dry happened here four days before my car was delivered. My dealer was well aware of that and said that they were checking ALL fluid levels during PDI. None the less, I'm taking my car in tomorrow morning to have the diff fluid checked again to satisfy the recall and to ease my concern. I haven't had any noises, smells or any other problems. I'm just being proactive.

I didn't ask the range of VIN #s covered by the recall. If you're near or below the OPs VIN, you might consider calling your dealer and finding out if you're in the range of the recall. I expected an email, postcard or call from GM or my dealer if I was in the range but received no notification. I guess they're treating it like many recalls and just satisfying it at the next service. Kind of an expensive way to operate in this case.

Rat

It's not a recall, it's Customer Satisfaction Bulletin #13384.

Here are the first paragraphs:You can see recalls here. There are none for the C7.

Thanks for the clarification. I reported what I was told by the service writer at my dealership after I specifically asked if it was a bulletin or a recall. What a surprise, inaccurate info from the dealer. :eek:

Reading the bulletin, though, looks like GM is just using semantics regarding a recall vs a bulletin. The corrective action, replacing the diff if there's almost any noise, seems like it should rise to level above a "Customer Satisfaction Bulletin." I realize GM really doesn't want the bad publicity that goes along with the recall, but there are a lot of owners that aren't on CF and may not have a clue that there's a potential problem with their car that could be easily remedied before it requires a diff change.

I couldn't make it in to have my diff checked today so I didn't get a chance to talk with them in person. My salesman assured me at delivery that the diff was checked, so I'm not too concerned but I'll take it in anyway for peace of mind.

Rat

Update

I got a call from the Service guy today. GM has authorized the replacement of the rear end. One interesting thing he told me was that GM doesn't have a supply of spare parts so they are going to have to pull a rear end from a car that is scheduled for production. I hope I'm not stealing one from a pre-sold order. I'm told that I should be able to pick up my car at the end of the week. Surprisingly I'm still pretty positive about the whole thing. It's unfortunate that it happened but I like the way GM has handled the issue quickly.