Vibration When Accelerating
Thread Starter
Member
Joined: Oct 2024
Posts: 225
Likes: 29
From: Pennsylvania, US
2008 C300 4Matic
Vibration When Accelerating
I have a 2008 C300 4Matic. When I accelerate lightly, the car gets like “waves” of vibrations. It sounds and feels almost like a pulsing sound you’d hear in a horror movie. This used to happen lightly and be a little noticeable, but somewhat recently it got worse and much more frequent. Now it happens more frequently, and I also noticed the RPM’s reflect the feeling now when they didn’t use to. When the pulsing is bad, you can visibly see the RPM needle going up or down (or only up if accelerating a little harder) by 200 RPM each time. This never happened before, and it’s very unpleasant to drive and worrying.
I know I need new engine mounts, but it still doesn’t explain the RPM part of it, and my mounts aren’t that bad. They have a slight vibration at idle when the engine is cold, but when warmed up it’s basically absent.
Could this be from low transmission fluid? I noticed that it’s much worse when the car is warmed up than when cold. I have everything I need to do a drain and fill + filter change on the transmission, minus the fluid and fill adapter I still need to pick up. To me it kind of sounds like a torque converter, but up until a few weeks ago it shifted so smoothly and never did this so I believe it may just be low on fluid, but not really sure.
Edit: On that note as well, what transmission fluid do you guys recommend? Genuine fluid or has anyone had any luck with that Fuchs Titan 4134 stuff?
I know I need new engine mounts, but it still doesn’t explain the RPM part of it, and my mounts aren’t that bad. They have a slight vibration at idle when the engine is cold, but when warmed up it’s basically absent.
Could this be from low transmission fluid? I noticed that it’s much worse when the car is warmed up than when cold. I have everything I need to do a drain and fill + filter change on the transmission, minus the fluid and fill adapter I still need to pick up. To me it kind of sounds like a torque converter, but up until a few weeks ago it shifted so smoothly and never did this so I believe it may just be low on fluid, but not really sure.
Edit: On that note as well, what transmission fluid do you guys recommend? Genuine fluid or has anyone had any luck with that Fuchs Titan 4134 stuff?
Last edited by hmclaughlin67; Jan 13, 2025 at 07:57 PM.
Member
Joined: Oct 2016
Posts: 77
Likes: 8
Mercedes C230 1997 W202
Hey,
Sounds like an annoying problem that has been creeping up over time.
With these symptoms it can be easier to diagnose from a video.
A hunch is bad ignition coil? Electronics tend to show issues when warm more so than when cold.
A misfire due to an erroneous ignition coil could lead to rough running under accelerqtion and sense of vibration, though from the front.
If it is from the rear, as weight transfer go to rear end of the car during acceleration, the drive syatem, rear tyres condition, balance and fit (if loose) could play a part.
These are all just some ideas that may help you along the way.
Edit: If rpm fluctuates as much as 200 rpm, lnly things I could think of is engine misfire, slipping, or erroneous rpm indication.
Sounds like an annoying problem that has been creeping up over time.
With these symptoms it can be easier to diagnose from a video.
A hunch is bad ignition coil? Electronics tend to show issues when warm more so than when cold.
A misfire due to an erroneous ignition coil could lead to rough running under accelerqtion and sense of vibration, though from the front.
If it is from the rear, as weight transfer go to rear end of the car during acceleration, the drive syatem, rear tyres condition, balance and fit (if loose) could play a part.
These are all just some ideas that may help you along the way.
Edit: If rpm fluctuates as much as 200 rpm, lnly things I could think of is engine misfire, slipping, or erroneous rpm indication.
Last edited by Shadedmoon; Jan 15, 2025 at 03:58 PM.
Thread Starter
Member
Joined: Oct 2024
Posts: 225
Likes: 29
From: Pennsylvania, US
2008 C300 4Matic
Hey,
Sounds like an annoying problem that has been creeping up over time.
With these symptoms it can be easier to diagnose from a video.
A hunch is bad ignition coil? Electronics tend to show issues when warm more so than when cold.
A misfire due to an erroneous ignition coil could lead to rough running under accelerqtion and sense of vibration, though from the front.
If it is from the rear, as weight transfer go to rear end of the car during acceleration, the drive syatem, rear tyres condition, balance and fit (if loose) could play a part.
These are all just some ideas that may help you along the way.
Edit: If rpm fluctuates as much as 200 rpm, lnly things I could think of is engine misfire, slipping, or erroneous rpm indication.
Sounds like an annoying problem that has been creeping up over time.
With these symptoms it can be easier to diagnose from a video.
A hunch is bad ignition coil? Electronics tend to show issues when warm more so than when cold.
A misfire due to an erroneous ignition coil could lead to rough running under accelerqtion and sense of vibration, though from the front.
If it is from the rear, as weight transfer go to rear end of the car during acceleration, the drive syatem, rear tyres condition, balance and fit (if loose) could play a part.
These are all just some ideas that may help you along the way.
Edit: If rpm fluctuates as much as 200 rpm, lnly things I could think of is engine misfire, slipping, or erroneous rpm indication.
I doubt it’s wheel related as well, and it’s certainly a drivetrain issue and not speed related. I did narrow it down today in that it only happens in 4th gear and up, which makes me think the transmission service might help a lot.
Joined: Nov 2016
Posts: 7,847
Likes: 3,498
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Just make sure you get this stuff and NOT the FE.
Last edited by JettaRed; Jan 16, 2025 at 09:09 AM.
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Member
Joined: Oct 2016
Posts: 77
Likes: 8
Mercedes C230 1997 W202
Another thought, hve you tried go into sport / manual mode? Will the car show the gear it is in when driving? Perhaps the gears are cycled, up/down, that could also impact the revs to fluctuate.
Last edited by Shadedmoon; Jan 18, 2025 at 07:45 AM.
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Thread Starter
Member
Joined: Oct 2024
Posts: 225
Likes: 29
From: Pennsylvania, US
2008 C300 4Matic
If OK in park and only on the road, indicates issue with slipping transmission? In park and neutral the transmission is disengaged.
Another thought, hve you tried go into sport / manual mode? Will the car show the gear it is in when driving? Perhaps the gears are cycled, up/down, that could also impact the revs to fluctuate.
Another thought, hve you tried go into sport / manual mode? Will the car show the gear it is in when driving? Perhaps the gears are cycled, up/down, that could also impact the revs to fluctuate.
Thread Starter
Member
Joined: Oct 2024
Posts: 225
Likes: 29
From: Pennsylvania, US
2008 C300 4Matic
I don’t have an MB specific reader as of yet, but I have an Innova 5610 and I couldn’t get any codes off it. I’m picking up the fluid shortly and will see if that helps.
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Joined: Oct 2012
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GL450
I have a 2008 C300 4Matic. When I accelerate lightly, the car gets like “waves” of vibrations. It sounds and feels almost like a pulsing sound you’d hear in a horror movie. This used to happen lightly and be a little noticeable, but somewhat recently it got worse and much more frequent. Now it happens more frequently, and I also noticed the RPM’s reflect the feeling now when they didn’t use to. When the pulsing is bad, you can visibly see the RPM needle going up or down (or only up if accelerating a little harder) by 200 RPM each time. This never happened before, and it’s very unpleasant to drive and worrying.
I know I need new engine mounts, but it still doesn’t explain the RPM part of it, and my mounts aren’t that bad. They have a slight vibration at idle when the engine is cold, but when warmed up it’s basically absent.
Could this be from low transmission fluid? I noticed that it’s much worse when the car is warmed up than when cold. I have everything I need to do a drain and fill + filter change on the transmission, minus the fluid and fill adapter I still need to pick up. To me it kind of sounds like a torque converter, but up until a few weeks ago it shifted so smoothly and never did this so I believe it may just be low on fluid, but not really sure.
Edit: On that note as well, what transmission fluid do you guys recommend? Genuine fluid or has anyone had any luck with that Fuchs Titan 4134 stuff?
I know I need new engine mounts, but it still doesn’t explain the RPM part of it, and my mounts aren’t that bad. They have a slight vibration at idle when the engine is cold, but when warmed up it’s basically absent.
Could this be from low transmission fluid? I noticed that it’s much worse when the car is warmed up than when cold. I have everything I need to do a drain and fill + filter change on the transmission, minus the fluid and fill adapter I still need to pick up. To me it kind of sounds like a torque converter, but up until a few weeks ago it shifted so smoothly and never did this so I believe it may just be low on fluid, but not really sure.
Edit: On that note as well, what transmission fluid do you guys recommend? Genuine fluid or has anyone had any luck with that Fuchs Titan 4134 stuff?
