I have an automatic 2016 BMW M4 with less than 30K miles. I hear a “thud” sound from the rear when I press the gas lightly or when I let go of it. It doesn’t matter if I accelerate/decelerate softly or abruptly, I still get a thud noise every time. There is NO noise when I shift gears up or down via the paddle shifters, only during acceleration/deceleration.
I’ve been scouring the internet and have been through many posts. A lot of things that came up were, differential, bushings, guibo, driveshaft U joint, moving parts in trunk etc.
I had my BMW dealership look at it and here is what they said:
“NORMAL DRIVETRAIN BACKLASH SOUND FOR THIS VEHICLE (IPS) THE SOUND FROM THE REAR OF THE VEHICLE UPON LOAD REVERSAL OF THE DRIVETRAIN IS INHERENT TO THIS VEHICLE. THE DRIVETRAIN IS MOUNTED SOLID. AND THE TRANSMISSION IS FIRMLY ENGAGED LIKE A MANUAL TRANSMISSION. THE SOUND IS NORMAL, AND NO REPAIR IS NECESSARY.”
Does anyone know what they mean by this? Drivetrain backlash, load reversal? Are they referring to changing gears? If they are, I don’t hear the sound when I change gears. I only hear it accelerating and when letting go of the gas.
The dealership also said the bushings and diff looked fine.
Its so annoying driving with this sound.
All the M cars have more drivetrain "lash" than other vehicles. The E46 M3 was terrible. They are set up "looser" because they really are race-track ready street cars. Unless the clunk is excessive, or extreme (and I would have to feel/hear it myself to judge), I would tend to agree with them.
ASE and BMW Master Certified Technician
Thanks for the reply. The clunk does seem excessive at times, the BMW Shop Foreman also thought so too. However, after him and his team checked, they couldn't find anything out of the ordinary.
Is there anything I should watch out for over the course of time?
Not really. Just if it gets worse over time. Which it shouldn't if it is the normal amount of built in lash.
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ASE and BMW Master Certified Technician
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