Hallo hoffe das Thema ist noch aktuell, habe zwecks des Klopfens meinen Gla jetzt ein neues Heckachsdifferenzial verpasst. Klopfen ist immernoch da lediglich wenn ich selber Schalte ist es weg.

 

Servus hoffe mal das Thema ist noch aktuell. Habe zwecks des Klopfens mein Auto jetzt ein neues Heckachsdifferenzial verpassen lassen. Klopfen ist immernoch da lediglich wenn ich selbst runterschalte ist es weg.

 

There seem to be a number of different problems people are having causing the 'clunking noise.
My understanding is it only occurs when there is a shift from power to drag felt from the rear. It seems as it the tolerances from the complex gearing combine when to power shifts from the engine driving to when the engine is braking. There is s knock type of sound, but only at very low speeds. Above was mentioned as a slack in the PTO gearing to the rear prop shaft. In the mix would be any slight out of phase dual clutch application. I can't remember when, but I have felt the same when using a farm tractor when there was a shift between the engine powering to the ending braking especially at low speed. I have a 2016 45 26K Kms.

 

There seem to be a number of different problems people are having causing the 'clunking noise.
My understanding is it only occurs when there is a shift from power to drag felt from the rear. It seems as it the tolerances from the complex gearing combine when to power shifts from the engine driving to when the engine is braking. There is s knock type of sound, but only at very low speeds. Above was mentioned as a slack in the PTO gearing to the rear prop shaft. In the mix would be any slight out of phase dual clutch application. I can't remember when, but I have felt the same when using a farm tractor when there was a shift between the engine powering to the ending braking especially at low speed. I have a 2016 45 26K Kms.

Definitely during downshifting and upshifting at low speeds.

 

My new 2025 gla250 clunks in rear cabin during shifting. Is there an update needed?

 

Start by changing the diff oil. That has fixed the clunk for many on this Forum.

 

Did this twice, back to back. Did nothing.

I decided to sell it. It was getting on my nerves. Great car otherwise. I'll miss it. Now I have a 2023 X3M, soon to have a JB4 so that it can have 600 at the flywheel (according to BurgerTuning )

 

Ive got the same problem with my 2015 Mercedes gla220d 4matic, although the noise is becoming more consistent even once I've been driving for 1hr+. Should I be concerned that the rear diff is going or has already gone?

 

I have heard the same noise in my GLA 250 2024. I’ve only had it two months, and it has just over 1000 miles on it. Have you found out anything more?

 

What is that pedal reset you ar mentioning?

 

Reset Transmission Adaptive Learning Pedal Travel

 

I have noticed a similar clunk when coming to a stop in D on my GLA and also in N, but the latter is much louder and can be physically felt, which I have noticed on our non-DCT GLE too.
I did the pedal reset yesterday and it has reduced/nearly eliminated any clunking in D, most unwanted transmission behaviours, and maybe 10% of the DCT's indecisiveness when picking which gear to be in.

 

Dual clutch transmissions are meant to be driven in a sporty manner in order for the computers to rev match and fluidly operate the clutches. If you slow down gradually often times the downshift to first can be harsh. It's a bit in the nature of the beast.

That being said, you can adapt your driving style to minimize this. Have you tried slowing down later and decelerating harder when coming to a full stop?

As with anything mechanical, some of these transmissions are smoother than others. Add in the computers attempting to mimic human inputs on the clutch pedal and a lot can happen.

But on line communication can leave a lot out. Sorry if the above is off mark.

 

I have a CLA45 2017 with the similiar clunking noise that people were describing here. When coming to a stop (rolling), the clunk can be heard downshifting mostly from 2nd to 1st. Had diff oil changed, had adaptation done, changed the transmission oil. Finally, went to authorized MB service to check if something is wrong with the software and asked to update it. I was informed that the transmission software was the newest, but it wasn't compatible with the main computer software. It was fixed and I was assured that the issue should be solved. They also did diagnostics 2x times (when buying the car and after the recent visit) and from their point of view the transmission works ideally. Result: thumping/clunking noise can still be felt going to a full stop. Maybe not so noticeably, but it's still there. Otherwise, the gearbox works fluently (upshifting, downshifting in an aggressive manner). While reading previous stories I really started to think that maybe it's the way it should be, due to the nature of the transmission. However, it still seems weird. Maybe someone else still has tips and what to try next?

 

Thank you for your quick response. I have scheduled an appt with the service center. I will look for a latest thread but I couldn’t find any other 2024 GLA thread so will start a new post for 2024 GLA for general observations and hopefully new members will chime in too

 

Hello I have a 2024 GLA 4matic that I bought in Jan and I have driven only 250 miles primarily on inside roads - I’ve noticed the clunk and shift noise while braking too or coming to a stop, sometimes when I park or when I start the car from a stop. It’s annoying to continually hear the clunking or shifting noise. I also find it extremely noisy when moving from D1 to D6. Does anyone here have similar experience with a 2024 car ?

 

Obviously on a brand new vehicle you're well within warranty so take it to dealership service and have them do a test drive and analysis. They may have missed something in delivery-prep, such as shipping blocks (suspension related but not transmission). Or perhaps the factory didn't properly fill the transmission/differential fluid. Again, take it to service.

This thread commenced in 2015 so some very good general insight but perhaps not specific to your 2024 situation. Not sure why you posted to a thread in the first generation 2014-2019 section and not the 2020+, as the latter is a quite different 2nd generation.

 

I have a 2015 GLA 250 with 114k miles on it. Lately there has been a "clunk" noise coming from the rear. I had the diff oil changed and it did not help. My mechanic tested it with and without the rear solenoid attached and confirmed that the differential needs to be replaced. He tested it in 2WD only and it runs just fine with no noise. Soooo................ We are thinking of just leaving it in 2WD for the time being and skipping the whole repair. we'll sort of evaluate how it goes day to day. Does anyone have an opinion on this? My mechanic doesn't see anything wrong with this, it just won't ever go into 4WD. we live in a mild climate so not really worried about snow, front wheel drive is usually all we ever need.

 

I just had my diff (and trans) replaced. The diff clunk is still there...unreal.

 

Moving forward ... motor oil changes at 5K miles with diff oil at 10K miles (every other oil change). These are both easy DIYs that will save you more than enough money on the first time to pay for the tools and more.

Then we get into what kind of motor oil and Ceratec or MoS2 or not. This can get emotional!!!!!

The diff gets the MB oil regardless of the high price.

 

Start by changing the diff oil. IMHO this needs to be done every 10K miles. Others on this Forum have found an oil change cured their problem. No guarantees, but an easy place to start.

 

I possess a GLA250 4-matic and have encountered persistent issues similar to those outlined here. Today, I brought it to the Mercedes-Benz service center, where they informed me that the likely culprit is the rear differential, and the repair will cost approximately $4000. My car has only traveled 85,000 kilometers and unfortunately, its warranty has recently expired. It's disheartening to realize that despite the premium ownership price, Mercedes-Benz isn't proving to be any better than an average car.

 

If you have the means.. try going under your car and grabbing the shafts that come out of the diff, there’s one on each side of it. If one or both has excessive play/can be easily moved by hand then a diff bearing is probably wearing. Someone stripped a diff from a CLA45 on the CLA forums and found ‘Made in China’ stamped on the worn bearing FWIW…

 

For sure. The trans shines, or at least doesn't disappoint, when driven hard. Not a good fit for the 250, marginally.more acceptable in the 45. The great 8 speed ZF makes all the sense in the world for both cars honestly. They make a transverse one don't they?

 

I brought my '15 in for the clunk and the occasional reverse grind in the cold (under a 6-month 3rd party warranty after purchasing used from a Mercedes dealership). They replaced the diff, after which they now say the trans is making odd noises. So it looks like they're going to try and replace the trans too.

Yikes, that's in the $12-15k neighborhood for the warranty company. Over half of what I paid of the car!

 

I brought my '15 in for the clunk and the occasional reverse grind in the cold (under a 6-month 3rd party warranty after purchasing used from a Mercedes dealership). They replaced the diff, after which they now say the trans is making odd noises. So it looks like they're going to try and replace the trans too.

Yikes, that's in the $12-15k neighborhood for the warranty company. Over half of what I paid of the car!

Yikes... at least it's not on your dime. I'm not sold on the DCT for the GLA anymore given that it doesn't seem well-suited for it. It's marketed as a city car in a way, but it's not great in stop-and-go traffic and is lurch-y at low speeds or when it's cold. There must be significant clutch wear in these situations. It's nice and quick on the highway and cruising speeds, but that doesn't happen much in town.

I've driven other DCT cars in the past with the same issues, except they have mainly been performance cars. I know there was a fad of putting DCTs in a lot of cars some years ago, but it seems that most companies have returned to CVTs or TC autos in following years, even performance cars (F80 M3 had a 7DCT, G80 has an 8-speed auto). Performance automatics are also now very fast but offer far more comfort and daily drive usability. The 9-speed auto in the GLE53 is as quick or quicker than the 7DCT in the GLA250. Not a totally fair comparison, but my point stands.

 

Hi there i got same problem.do you know what happen it is? Please

 

Welcome. Lots of replies outlining the cause in this thread. It's either a transmission issue or rear differential, the latter of which only applies to 4MATIC models.

 

I have a GLA 220 2014 and 55000 miles.

i have a knocking noise only if I am at speed of 0-25mph, in drive mode

Both if I accelerate and if i don't accelerate or IF I break.

the noise increases in frequency if I turn right or left.

no knocking noise in neutral and rear.


do you think is the differential?
thanks in advance to everyone!

 

The dual-clutch prepares the next for the next gear based on how you are driving. If speeding up, it prepares the next upshift gear to be ready to engage, or if slowing down, it will prepare the next downshift to engage. If you are slowing down and the clutch is getting ready for the downshift and you change and hit the pedal to speed up, you can get a rough shift, and what goes with an unplanned change shift of gears.

 

DCTs are performance gear boxes. A lot of software has been developed to make them drive gently, mimicking a torque convertor automatic. But at the end of the day you have a computer attempting to feather a clutch pedal.

These transmissions perform best when they are driven aggressively. Otherwise they will buck and stutter a bit from time to time. It's just their nature, especially when downshifting a you coast to a stop. Brake / stop more aggressively and the problem diminishes and generally completely goes away.

 

I have noticed a slight "clunk" as well when coming to a stop if the car is very cold. I have determined that it is the transmission shifting from 2nd to 1st after the car stops moving. It also goes away after a bit of driving, likely after things have loosened up and fluids are less viscous.

I noticed the noise is more pronounced and noticeable following DIY transmission reset, likely the car is returning to a factory TCU tune and the sound becomes less frequent over time. As of now, I don't hear any sounds as it's been a few months since my last reset. the car has probably adapted to my driving style and changed shifting accordingly.

DCTs are performance gear boxes. A lot of software has been developed to make them drive gently, mimicking a torque convertor automatic. But at the end of the day you have a computer attempting to feather a clutch pedal.

These transmissions perform best when they are driven aggressively. Otherwise they will buck and stutter a bit from time to time. It's just their nature, especially when downshifting a you coast to a stop. Brake / stop more aggressively and the problem diminishes and generally completely goes away.

Yes, I've noticed that the car tends to be an indecisive and shifty at low speeds, particularly when cold. It can be annoying when it can't decide between 3rd to 4th from 30-40 kmh. I deal with it any time I drive the car because I can only get up to 30 or 35 in my residential area, and the speed limit on my uni campus is 40, so constant changing from 3-4 rough pick up exiting a turn or corner as the clutch reengages.
I have resorted to using manual mode on campus since I constantly have to stop for oblivious pedestrians who just walk out in front of you or stop for people making a turn since they're single-lane roads and I can't go around.

I'd like to meet the genius that decided to make the city car-oriented and terrible for public transportation, and then make the university bad for cars. You just can't win in life I guess.

 

This is because the car has a dual clutch gearbox which is known as a transverse gearbox which switches from two wheel drive to four-wheel-drive so it’s just the characteristics of the car with it engaging the diff from two wheel drive to four-wheel-drive it’s normal in a lot of AMG 45 or 63 is or even any of the 4 matic hopefully this is useful information as I had so many garages look at my GL a 45 and they couldn’t find anything wrong with it it is just the characteristics of the car even on YouTube there are car viewers that say the same thing but you have to get used to it