LTK

Can anyone tell me, does the 2018 GLA have a separate transfer case? I believe the grinding slipping sound I am hearing when I make sharp corners is that. I had found an old post that described perfectly my car's problem. It was dated 3-17-2012 by pa-hawk with a service bulletin issued 01-28-09, with the fix to change the fluid in the transfer case.

I just came back from the dealer. Merc Benz service foreman informed me it is the rear differential. Ugh, 6K repair bill. He disconnected the rear differential solenoid, and the car ran fine. Next time trust my gut, even for a vague sound. If I would have gotten the car there 8K miles earlier it would have been covered under warranty...sigh

Audi Junkie

Yes. Change the TC fluid. Dexron VI....do it twice.

LTK

merc benz shop foreman looked at it...it is the rear differential needs to be replaced

Audi Junkie

They are there to take your money. Why don't you just try to change the diff oil?

LTK

would like to, but foreman said all one with the transmission, not a separate TC with oil. He did offer to flush twice for $500.

Audi Junkie

Hmm. Keep looking for advice here or find an indy mechanic, I use BOSCH Service Centers

LTK

I went with the mechanic at Merc Benz and had the rear differential replaced. Bill was $5K, MercBenzUSA kicked in goodwill $2K since it was a known service bullitin and my car fell just outside the parameters of warranty. So the car is running great, no more noise or problems with the rear end on turning or accelerating. I'm happy about that!

BMW&PorscheDude

Wow! I know that I am reviving an old thread, but I was searching on a related issue, and wanted to add some substance to this thread. I just purchased a 2018 Infiniti QX30 which is a Mercedes GLA250 in Infiniti clothing. The car has 213K miles and I didn't know that the powertrain was all Mercedes GLA250 until after I had to address some issues. I had the same noise in the drivetrain as the OP, so I searched and read. I got underneath the car and disconnected the electrical connector to the rear differential solenoid, and the car ran fine, no noise. You will see a warning on the dash that the AWD is inoperable. That's because the rear diff is not being controlled, so it has become a FWD vehicle that that point.

I was concerned that the rear diff was bad, so I found a good used rear diff on eBay for a fair price with free shipping, from a 35K donor vehicle. It was from a reputable dismantler seller, so I was willing to take the risk on the part. While I was waiting for the diff to arrive, I drained and refilled the rear diff fluid. I was able to do it without even raising the vehicle. It was super easy and fast. While I was under the vehicle, I reconnected the solenoid for the rear diff. And then I drove the car, and the problem was solved! It drives like a dream, and no noise! I always say that what scares me the most is what I can't see. We can't see the fluid in these closed cases, so we need to change the fluids if we have any doubts, especially as our cars gain more miles. Do it sooner, rather than later, especially if you want you vehicle to last. I appreciate the message about doing it twice, and now I will. Again, it's super easy, fast and cheap. I have a feeling that the rear diff fluid in my vehicle was never changed in 213K miles. How sad.... :-(

On a side note, I had a 30-day return availability on the good used rear diff that I had purchased, so I waited for a bit while I drove the car. The rear diff was fine, so I returned the eBay diff, without ever opening the packaging. It cost me $135 for return shipping, but I felt confident that I had solved the problem with a simple fluid change. I didn't want to store the eBay diff and I just wanted my money back. I was willing to pay the $135 return shipping penalty for a purchase that I made in error.

So sorry that the OP may have been fleeced by the dealer, when they probably only needed a fluid change in the rear diff.

LTK

Excellent, glad you did post, never to late! I never knew about Infiniti in GLA250 stealth mode! I am going to keep up on the diff oil change every 70K miles. I'm due now to have it done in a month. Better safe then sorry. Otherwise the car has been a real workhorse with no problems. Good buy, car now has 117K miles.