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Hi all, I recently took a 2015 GLA45 for a 24 hour test drive. The car has 40k miles and the carfax looks like the previous ownership (2 owners) took very good care of the car. All of the maintenance history was done at the same Mercedes dealership. So, I had the car for 24 hours and it was awesome. I thought it drove pretty good and thought it was mostly normal. I had heard complaints over the transmission so expected it to not be perfect. I mentioned some transmission concerns about the car to confirm if anything went wrong their warranty would cover it. I also mentioned one instance while driving the car, there was a large downshift delay at about 3000-4000 rpm. It was stuck for a few seconds then finally went down. He went to go and take the car for a drive to see if he thought anything was wrong, and he came back with a few concerns:

- When reversing, the car would take a few seconds to finally start reversing. When I had the car, I noticed the e-brake light would always be on upon start up. I just pulled it off and pressed the gas to reverse and thought it was normal.

- He thought the acceleration was a bit jerky. I noticed this as well and thought it was normal for the car.

- His main concern was the throttle.

They are having their techs look at it on Monday and fix whatever the issue is before they sell it to me. Obviously I appreciate the honestly on their end instead of pretending like everything is all good. Anyone have any idea what it could be? Kind of curious before they call me on Monday. I don't want to let this scare me off buying the car as it is in great condition, and Carmax has the 30/day buy back and 90/day limited warranty; also purchasing the extended warranty. And the fact that everything is documented before I am even buying it, I'm not too worried. But let me know yall's thoughts. Thanks!
 

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2015 had a combination of DCT delay with a small motor and big turbo. The throttle tends to lag when starting from a stop. This was addressed (a bit) with the 2016 model year. But without driving the car I can't tell you if what you have is normal or not.

There is a transmission reset procedure (as well as throttle) that can reset the parameters which will change as you drive to adjust to your style.
 

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Discussion Starter · #3 ·
2015 had a combination of DCT delay with a small motor and big turbo. The throttle tends to lag when starting from a stop. This was addressed (a bit) with the 2016 model year. But without driving the car I can't tell you if what you have is normal or not.

There is a transmission reset procedure (as well as throttle) that can reset the parameters which will change as you drive to adjust to your style.
That seemed normal. The sales person was more worried about the car not reversing. I just pressed on the gas to reverse when I had it, but according to him he put the car in reverse and didn't put his foot on the gas, and it took a few seconds to start reversing. Does that sound like a common issue?
 

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Without being there it is hard to say. For instance ... If he went from park to reverse then it would not engage until he either pressed the gas or released the parking brake (same for forward drive).
 

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2020 MB GLA250 4MATIC Avantgarde Edition
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Parking brake always activates automatically on automatic transmission Mercedes cars. The brake should automatically disengage when the car is put in gear too, unless it’s on a slope.

as far as their repair, it’s free and they are doing it without you asking. I see no problem. Relax And let them do their thing, if it’s an issue they’ll take care of it. If there’s no issue, don’t let it scare or bother you unless you notice something is wrong. Once you get the car, do the reset procedure that Wayne mentioned.

best of luck with your new car, welcome!
 

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If you are in Park the electric rear brake is activated. A few things ...

Putting it in drive or reverse does not release the parking brake until you press the gas. This gives a rough start. I manually release the brake before driving off.

Since park automatically sets the brake, if your brakes are hot when you stop the car to get out this pad pressure can warp the rotors. In this case, once park is selected you can manually release the brake.
 

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Sounds like carmax doesn’t see many AMG’s lol. Just tap the gas pedal once quickly to release the e brake when ‘PARK’ is illuminated on the dash.

Couple things I’d do.. Check to make sure the transmission has been serviced at least once and the rear diff at least a couple times. Trans is every 30k and diff is every 10k, so the maintenance schedule says the diff should have been serviced 4 times by now and trans once.
 

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Hi all, I recently took a 2015 GLA45 for a 24 hour test drive. The car has 40k miles and the carfax looks like the previous ownership (2 owners) took very good care of the car. All of the maintenance history was done at the same Mercedes dealership. So, I had the car for 24 hours and it was awesome. I thought it drove pretty good and thought it was mostly normal. I had heard complaints over the transmission so expected it to not be perfect. I mentioned some transmission concerns about the car to confirm if anything went wrong their warranty would cover it. I also mentioned one instance while driving the car, there was a large downshift delay at about 3000-4000 rpm. It was stuck for a few seconds then finally went down. He went to go and take the car for a drive to see if he thought anything was wrong, and he came back with a few concerns: - When reversing, the car would take a few seconds to finally start reversing. When I had the car, I noticed the e-brake light would always be on upon start up. I just pulled it off and pressed the gas to reverse and thought it was normal. - He thought the acceleration was a bit jerky. I noticed this as well and thought it was normal for the car. - His main concern was the throttle. They are having their techs look at it on Monday and fix whatever the issue is before they sell it to me. Obviously I appreciate the honestly on their end instead of pretending like everything is all good. Anyone have any idea what it could be? Kind of curious before they call me on Monday. I don't want to let this scare me off buying the car as it is in great condition, and Carmax has the 30/day buy back and 90/day limited warranty; also purchasing the extended warranty. And the fact that everything is documented before I am even buying it, I'm not too worried. But let me know yall's thoughts. Thanks!
Hi There! Just a warning, these cars go thru differentials at low miles (mine went out at 50K) , costing $6000.00. This is is not isolated and Mercedes’ doesnt cover it. Be careful! Susan
 

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Hi There! Just a warning, these cars go thru differentials at low miles (mine went out at 50K) , costing $6000.00. This is is not isolated and Mercedes’ doesnt cover it. Be careful! Susan
That’s a good point to make. It’s happened a fair bit now and transmissions as well. If either of those happen to my car, I’m just selling it as is
 

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Sorry to hear of your out of pocket expense Susan. I see from your prior thread input that you have a 2015 GLA [250?] 4-Matic. This thread is entitled GLA45 so one might assume harder wear on the differential given much higher performance. So particularly disconcerting if yours is the generally more operationally pedestrian 250.

What exactly did they find was the root cause, or if indeterminant what did they list as the damage and/or repair/replacement procedure? I don't see any specifics here nor in your prior input.

I'm less clear on your point. What would you recommend to "be careful?" Less mechanically stressful driving? More frequent inspection and fluid changes? Not retaining the vehicle beyond 50K miles. All of the above?

You also prior cited that "It happens to so many GLA’s that Mercedes [dealership service?] actually keeps the differential in stock!" Did your service advisor convey same?

As a GLA-dedicated site, and thereby more technically inclined, we appreciate greater insight. Thanks.
Hi There! Just a warning, these cars go thru differentials at low miles (mine went out at 50K) , costing $6000.00. This is is not isolated and Mercedes’ doesnt cover it. Be careful! Susan
That’s a good point to make. It’s happened a fair bit now and transmissions as well. If either of those happen to my car, I’m just selling it as is
 

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Sorry to hear of your out of pocket expense Susan. I see from your prior thread input that you have a 2015 GLA [250?] 4-Matic. This thread is specifically GLA45 so one might assume harder wear on the differential given much higher performance. So particularly disconcerting if yours is the generally more operationally pedestrian 250.

What exactly did they find was the root cause, or if indeterminant what did they list as the repair/replacement procedure? I don't see any specifics here nor in your prior input.

I'm less clear on your point. What would you recommend to "be careful?" Less mechanically stressful driving? More frequent inspection and fluid changes? Not retaining the vehicle beyond 50K miles. All of the above?

As a GLA-dedicated site, and thereby more technically inclined, we appreciate greater insight. Thanks.
Good Morning,
2015 GLA250 First edition 4-matic. No replacement from Mercedes, Mechanics (2) said it was a problem with the GLA. If you look up the GLA (250) in former threads, some have replaced the differentials twice, and 1 guy had replaced it 3 times with over 150K miles. Being careful means being watchful and aware this is a problem. And crazy as this sounds, MB has these parts readily available.The mechanics tell us thats because its more than a common problem. The differential should be checked (serviced)every 10K miles. Even then, they have still been a problem. Also, when I purchased the car, all service records were done by MB.
Susan
 

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The E-brake will engage whenever you put the car in Park. However, once you shift from Park to Drive or reverse, the E-brake will disengage automatically.

The vehicle has had two previous owners, and who knows how many test drivers and Carmax employees have driven the car. A reset of the transmission and throttle pedal is probably needed. The vehicle leans driving styles and based on driving style will adapt to the changing of gears based on driving style. Doing a reset puts all settings back to zero, and in something like a hundred miles, it will learn your driving style, and the gear shifting will be to your liking.
 
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