Violent thud when letting off at 4 grand
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Violent thud when letting off at 4 grand
so i have a 2006 e55 amg with a 77mm pulley and tune! Just replaced the motor mounts as they where bad and I thought they would fix the jerk! Essentially what happens is when I let off the gas at high rpm I get a very pronounced jerk threw the car almost like when a car with an SMG tranny shifts gears! Although the thud is now less severe with the new motor mounts it is still there! It didn't do this when the car was stock even with the bad motor mounts!
Anyone no what it could be? Torque converter?
Anyone no what it could be? Torque converter?
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Joined: May 2017
Posts: 74
Likes: 6
From: NJ
'03 E55, '00 GS300, '15 745I '13 M6 Gran Coupe
I would say get the car on a lift and inspect all the mounts. RWD cars are always known for this when the tranny mount is bad. More power is exposing an already existing issue.
Super Member
Joined: Jan 2016
Posts: 599
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2004 E55
I would definitely do the Transmission mount if you have not as well as the flex discs front and rear.
How long has it been since your last transmission service?
Smell your trans fluid, does it smell like a burnt clutch?
Also have you flushed your rear diff since ownership?
A conductor plate swap, fluid flush could be in your future or possibly a new transmission at worst.
Harsh downshifts are indicating a large problem. Like mentioned, the issue probably existed before and has become more pronounced with your increased power and you are finding the a weakening link.
How long has it been since your last transmission service?
Smell your trans fluid, does it smell like a burnt clutch?
Also have you flushed your rear diff since ownership?
A conductor plate swap, fluid flush could be in your future or possibly a new transmission at worst.
Harsh downshifts are indicating a large problem. Like mentioned, the issue probably existed before and has become more pronounced with your increased power and you are finding the a weakening link.
Last edited by BoostedAero; Jul 17, 2017 at 12:17 PM.
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Joined: Apr 2017
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From: Tampa Bay, FL
05 E55, 98 CLK320
How do you guys know that it isn't overboost/supercharger clutch spacing causing this?
Because I am having the same issue, it happens on engagement and disengagement it feels like. A few hard pulls and it engages smoothly, but if I drive it slowly in traffic for a day or two the car will begin to feel really wonky, shaky, lazy, supercharger engagement is extremely jerky like someone is punching me in the back of the head.
Doing solid mounts with my headers at the shop and while the car is there I'll do the tranny mount too but I have a feeling my supercharger clutch spacing is out of spec, and it makes sense because I have a huge crank pulley harshing on it every day.
I have new flex discs, just did the diff fluid, this problem has been there since I got the car really.
Because I am having the same issue, it happens on engagement and disengagement it feels like. A few hard pulls and it engages smoothly, but if I drive it slowly in traffic for a day or two the car will begin to feel really wonky, shaky, lazy, supercharger engagement is extremely jerky like someone is punching me in the back of the head.
Doing solid mounts with my headers at the shop and while the car is there I'll do the tranny mount too but I have a feeling my supercharger clutch spacing is out of spec, and it makes sense because I have a huge crank pulley harshing on it every day.
I have new flex discs, just did the diff fluid, this problem has been there since I got the car really.
Last edited by MACEDON; Jul 17, 2017 at 12:55 PM.
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From: Worldwide
2007 Mercedes E63 AMG
in my experience, what you explain generally would be a busted transmission mount. also i'd check your rear driveline failed bushings on the rear can have a similar effect. some here have had issues with subframe bolts pulling out.
Thread Starter
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Joined: Jun 2017
Posts: 112
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I would definitely do the Transmission mount if you have not as well as the flex discs front and rear.
How long has it been since your last transmission service?
Smell your trans fluid, does it smell like a burnt clutch?
Also have you flushed your rear diff since ownership?
A conductor plate swap, fluid flush could be in your future or possibly a new transmission at worst.
Harsh downshifts are indicating a large problem. Like mentioned, the issue probably existed before and has become more pronounced with your increased power and you are finding the a weakening link.
How long has it been since your last transmission service?
Smell your trans fluid, does it smell like a burnt clutch?
Also have you flushed your rear diff since ownership?
A conductor plate swap, fluid flush could be in your future or possibly a new transmission at worst.
Harsh downshifts are indicating a large problem. Like mentioned, the issue probably existed before and has become more pronounced with your increased power and you are finding the a weakening link.
Senior Member
Joined: Mar 2015
Posts: 386
Likes: 22
From: Tx
04 55
fixed pulley will resolve this
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Joined: Apr 2017
Posts: 1,120
Likes: 80
From: Tampa Bay, FL
05 E55, 98 CLK320
Super Member
Joined: Jan 2016
Posts: 599
Likes: 120
2004 E55
If you are approaching 100k miles and you do not have documentation of replacement, I would just do it as proactive maintenance. I think the Trans mount is about ~$45ish, both flex discs are about ~$95ish each too
One would support the end of the gearbox then inspect the gearbox mount for cracks in the rubber after you remove it, I doubt you can inspect the whole mount with it on the car. It is kinda hard to see all the way around the rubber
You will be able to see cracks in the flex discs as well...they are easier to inspect as they are exposed (and exposed to the elements too) I would bet anyone with about 100k miles has crack in theirs
They are on my list when I put the new trans in
One would support the end of the gearbox then inspect the gearbox mount for cracks in the rubber after you remove it, I doubt you can inspect the whole mount with it on the car. It is kinda hard to see all the way around the rubber
You will be able to see cracks in the flex discs as well...they are easier to inspect as they are exposed (and exposed to the elements too) I would bet anyone with about 100k miles has crack in theirs
They are on my list when I put the new trans in
Last edited by BoostedAero; Jul 18, 2017 at 01:24 PM.
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From: Worldwide
2007 Mercedes E63 AMG
yeah...sadly bad transmission or rear subframe bushings/mounts are hard to see. when you do see it is when the bushing/mount is missing huge chunks.
your local shop should be able to loosen a few items and easily push things around. if its out of normal spec for a vehicle that mount is dead. good bushings/mounts shouldn't allow for much movement by a human.
MACEDON yours doesn't sound like a mount or bushing. yours is probably your supercharger clutch, or possibly your transmission shifting wonky. when my transmission was 1 quart low on fluid it was shifting real real wonky. i'd do a bit more research for symptoms. i own a E63 so others should be of better assistance. or record a video of it and post up.
your local shop should be able to loosen a few items and easily push things around. if its out of normal spec for a vehicle that mount is dead. good bushings/mounts shouldn't allow for much movement by a human.
MACEDON yours doesn't sound like a mount or bushing. yours is probably your supercharger clutch, or possibly your transmission shifting wonky. when my transmission was 1 quart low on fluid it was shifting real real wonky. i'd do a bit more research for symptoms. i own a E63 so others should be of better assistance. or record a video of it and post up.
Last edited by hachiroku; Jul 18, 2017 at 12:58 PM.
MBWorld Fanatic!
Joined: Apr 2017
Posts: 1,120
Likes: 80
From: Tampa Bay, FL
05 E55, 98 CLK320
If you are approaching 100k miles and you do not have documentation of replacement, I would just do it as proactive maintenance. I think the Trans mount is about ~$45ish, both flex discs are about ~$95ish each too
One would support the end of the gearbox then inspect the gearbox mount for cracks in the rubber after you remove it, I doubt you can inspect the whole mount with it on the car. It is kinda hard to see all the way around the rubber
You will be able to see cracks in the flex discs as well...they are easier to inspect as they are exposed (and exposed to the elements too) I would bet anyone with about 100k miles has crack in theirs
They are on my list when I put the new trans in
One would support the end of the gearbox then inspect the gearbox mount for cracks in the rubber after you remove it, I doubt you can inspect the whole mount with it on the car. It is kinda hard to see all the way around the rubber
You will be able to see cracks in the flex discs as well...they are easier to inspect as they are exposed (and exposed to the elements too) I would bet anyone with about 100k miles has crack in theirs
They are on my list when I put the new trans in
yeah...sadly bad transmission or rear subframe bushings/mounts are hard to see. when you do see it is when the bushing/mount is missing huge chunks.
your local shop should be able to loosen a few items and easily push things around. if its out of normal spec for a vehicle that mount is dead. good bushings/mounts shouldn't allow for much movement by a human.
MACEDON yours doesn't sound like a mount or bushing. yours is probably your supercharger clutch, or possibly your transmission shifting wonky. when my transmission was 1 quart low on fluid it was shifting real real wonky. i'd do a bit more research for symptoms. i own a E63 so others should be of better assistance. or record a video of it and post up.
your local shop should be able to loosen a few items and easily push things around. if its out of normal spec for a vehicle that mount is dead. good bushings/mounts shouldn't allow for much movement by a human.
MACEDON yours doesn't sound like a mount or bushing. yours is probably your supercharger clutch, or possibly your transmission shifting wonky. when my transmission was 1 quart low on fluid it was shifting real real wonky. i'd do a bit more research for symptoms. i own a E63 so others should be of better assistance. or record a video of it and post up.
When in manual and under heavy load (gas pedal halfway down and below) my shifts are relatively tough, I chalked it up to just regular 722.6 behavior. In C or S the car shifts smooth if I drive slow, the gear changes don't feel tough until I step on it quite a bit.
I gotta check my fluid level sometime soon but I had the fluid serviced at a reputable shop in the are for the sole purpose of the guy getting the level right because I can never seem to do it in my other cars with the dipstick.
Last edited by MACEDON; Jul 19, 2017 at 02:05 PM.
