e92 m3 rear diff problem

peterv · 10-26-2008, 05:14 AM

I have noticed this just recently: I am in second gear and I am at 8000 rpm and I stop accelerating for a second then a second later I mash the gas pedal, the car jerks and makes a noise. I thought it was because of something in the trunk banging around, I cleaned out my trunk, but it still makes that noise. It doesn't seem to do these noises if I drive normally (between 2krpm and 4krpm) ie driving normal. This jerking and noise happens whenever I try to accelerate while I am revving high already. What could it be?

Crimson92 · 10-26-2008, 02:30 PM

It's normal, it's just the diff dong it's job

peterv · 10-26-2008, 06:54 PM

Quote:

Originally Posted by Crimson92

It's normal, it's just the diff dong it's job

There is a clear audible noise in the cabin when I hit the accelerator and it jerks forward, the noise is like a thump. I tried today and it does it even at 4krpm ranges, this is not normal operation of the car. It feels like I am hurting my car. It's Sunday so I am going to have to wait till tomorrow to bring it in.
I can cause multiple thumps if I keep hitting the gas and taking my foot off it, it seems whenever I put a load on it too fast it makes a thump.

Crimson92 · 10-26-2008, 08:56 PM

if you have ever driven a car with a locking diff the noise would not suprise you

watrob · 10-26-2008, 09:33 PM

Take it to the dealer, they have a product that they put in the diff called FMBooster, there is a bulletin on it. They did the same for the e46 M3 diff.

alpineweissM3 · 10-27-2008, 06:22 AM

Maybe it's a torn subfloor handed down from the e46!

peterv · 10-27-2008, 02:45 PM

Turns out you guys were wrong (no FM Booster and it wasnt regular operation of my car), I took it to the dealer and apparently a scew or bolt that attaches the diff to the chassis was messed up. I went to the dealer and have one of the technicians drive the car with me and we could both hear the noise, he parks it and looks at the underside of the car and he sees the diff at an angle, like hanging down a bit. As I saw my car drive off in the repair bay I saw the angle of the whole diff move around as he put more or less load on it. Basically, one side off the diff wasn't attached to the car.

satakal · 10-27-2008, 02:54 PM

"nothing to worry about"

ok.....

That's scary. Good thing its getting fixed. Hey... wait a sec... you wouldn't have possibly discovered this issue in a parking lot with cones it in? I mean... 8k rmp isn't exactly something you would do every day.
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Crimson92 · 10-27-2008, 02:54 PM

Quote:

Originally Posted by peterv

Turns out you guys were wrong (no FM Booster and it wasnt regular operation of my car), I took it to the dealer and apparently a scew or bolt that attaches the diff to the chassis was messed up. I went to the dealer and have one of the technicians drive the car with me and we could both hear the noise, he parks it and looks at the underside of the car and he sees the diff at an angle, like hanging down a bit. As I saw my car drive off in the repair bay I saw the angle of the whole diff move around as he put more or less load on it. Basically, one side off the diff wasn't attached to the car.

that seems off...if the diff were half on you would feel really bad vibrations not just a clunk

Phil325 · 10-27-2008, 03:37 PM

it's a Good thing you found out the problem in time before any irreversible damage happened.

Crimson92 · 10-27-2008, 05:02 PM

Quote:

Originally Posted by Phil325

it's a Good thing you found out the problem in time before any irreversible damage happened.

had anything happend it would have been bmws problem not his

killjohnnyforan · 10-27-2008, 08:01 PM

Quote:

Originally Posted by satakal

"nothing to worry about"

ok.....

That's scary. Good thing its getting fixed. Hey... wait a sec... you wouldn't have possibly discovered this issue in a parking lot with cones it in? I mean... 8k rmp isn't exactly something you would do every day.

its something i'd do everyday

gthirtyfizle · 10-27-2008, 08:07 PM

Its something I DO everyday

watrob · 10-27-2008, 08:21 PM

Like I said take it to the dealer?

satakal · 10-27-2008, 11:01 PM

Quote:

Originally Posted by killjohnnyforan

its something i'd do everyday

I'm pretty sure he doesn't redline his car on the daily.

And... I think he took a trophy at the autox with that loose bolt.

"why would that moron with the 335 make reference to a parking lot and cones? I don't know, whatever. Let me show off now."
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10-26-2008, 05:14 AM	#1
peterv Registered 3 Rep 3 Posts Drives: 2008 BMW M3 6Spd Join Date: Oct 2008 Location: San Diego, CA iTrader: (0)	e92 m3 rear diff problem I have noticed this just recently: I am in second gear and I am at 8000 rpm and I stop accelerating for a second then a second later I mash the gas pedal, the car jerks and makes a noise. I thought it was because of something in the trunk banging around, I cleaned out my trunk, but it still makes that noise. It doesn't seem to do these noises if I drive normally (between 2krpm and 4krpm) ie driving normal. This jerking and noise happens whenever I try to accelerate while I am revving high already. What could it be?
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10-26-2008, 02:30 PM	#2
Crimson92 Smiling Politely 1575 Rep 29,119 Posts Drives: Like a boss Join Date: Jun 2007 Location: Whales Vagina iTrader: (3)	It's normal, it's just the diff dong it's job
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10-26-2008, 08:56 PM	#4
Crimson92 Smiling Politely 1575 Rep 29,119 Posts Drives: Like a boss Join Date: Jun 2007 Location: Whales Vagina iTrader: (3)	if you have ever driven a car with a locking diff the noise would not suprise you
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10-26-2008, 09:33 PM	#5
watrob Lieutenant Colonel 140 Rep 1,597 Posts Drives: MY2022 X5 M-Sport 45e White Join Date: Sep 2008 Location: Brisbane - Australia iTrader: (0) Garage List 2021 Toyota Yaris Z ... [0.00] 2022 BMW X5 G05 e45 [0.00] 2015 Ferrari Cali T [0.00]	Take it to the dealer, they have a product that they put in the diff called FMBooster, there is a bulletin on it. They did the same for the e46 M3 diff. __________________ MY22 X5 M-Sport 45e White, 22"rims, Red Calipers, Ceramic Pads. Better off saying what it does not have and that's a B&O Audio System, otherwise all option boxes are ticked.
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10-27-2008, 06:22 AM	#6
alpineweissM3 I love my beautiful wife! 24 Rep 632 Posts Drives: e90 ///M Join Date: Oct 2007 Location: Pittsburgh iTrader: (0)	Maybe it's a torn subfloor handed down from the e46!
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10-27-2008, 02:45 PM	#7
peterv Registered 3 Rep 3 Posts Drives: 2008 BMW M3 6Spd Join Date: Oct 2008 Location: San Diego, CA iTrader: (0)	Turns out you guys were wrong (no FM Booster and it wasnt regular operation of my car), I took it to the dealer and apparently a scew or bolt that attaches the diff to the chassis was messed up. I went to the dealer and have one of the technicians drive the car with me and we could both hear the noise, he parks it and looks at the underside of the car and he sees the diff at an angle, like hanging down a bit. As I saw my car drive off in the repair bay I saw the angle of the whole diff move around as he put more or less load on it. Basically, one side off the diff wasn't attached to the car.
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10-27-2008, 02:54 PM	#8
satakal Major 99 Rep 1,476 Posts Drives: e46 Join Date: Nov 2007 Location: socal iTrader: (2)	"nothing to worry about" ok..... That's scary. Good thing its getting fixed. Hey... wait a sec... you wouldn't have possibly discovered this issue in a parking lot with cones it in? I mean... 8k rmp isn't exactly something you would do every day. ________ Jaguar V12 Engine Picture ________ Sick From Prilosec Last edited by satakal; 09-13-2011 at 11:39 PM..
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10-27-2008, 03:37 PM	#10
Phil325 Major 16 Rep 1,011 Posts Drives: 06 SGM E90 Join Date: Jul 2007 Location: West Melbourne, Fl/Jacksonville, FL iTrader: (0) Garage List 2006 325i [10.00]	it's a Good thing you found out the problem in time before any irreversible damage happened.
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10-27-2008, 08:07 PM	#13
gthirtyfizle Colonel 192 Rep 2,863 Posts Drives: E92 M3 AW Join Date: Jul 2008 Location: NYC iTrader: (4)	Its something I DO everyday
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10-27-2008, 08:21 PM	#14
watrob Lieutenant Colonel 140 Rep 1,597 Posts Drives: MY2022 X5 M-Sport 45e White Join Date: Sep 2008 Location: Brisbane - Australia iTrader: (0) Garage List 2021 Toyota Yaris Z ... [0.00] 2022 BMW X5 G05 e45 [0.00] 2015 Ferrari Cali T [0.00]	Like I said take it to the dealer? __________________ MY22 X5 M-Sport 45e White, 22"rims, Red Calipers, Ceramic Pads. Better off saying what it does not have and that's a B&O Audio System, otherwise all option boxes are ticked.
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