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-   -   Loud Diff Clunk (http://www.bimmerfest.com/forums/showthread.php?t=580861)

BlackStarMiG 11-11-2011 11:27 AM

Loud Diff Clunk
 
ok its made that sound since i bought the car in February but it wasn't this bad it happens when I accelerate from a stop and when high rpm shifts are made. at first i thought it was the normal m3 diff clunk but eventually it got to the point where when i made high rpm shifts or accelerated fast it felt light someone was hitting the underbody of my car with a hammer ( a big hammer) now im just afraid of driving hard or even gong any higher than S1 on my SMG its been like this for a while and this morning i decided to check if it was the rear diff bushings so i lifted the back end and tried ti see if the diff had any movement and it turns out they are still good there wasn't any movement with the diff also the subframe bushings are good as well and so is the Guibi or whatever u call it the rubber spacer between the driveshaft and the Diff. so i guess my question is:

1. Where else is the sound coming from it feels like mid to rear clunk.

2. Could it be the Driveshaft center support? :dunno:

3. i need to fix this please help :(

Matt P. 11-11-2011 12:56 PM

Quote:

Originally Posted by BlackStarMiG (Post 6435389)
ok its made that sound since i bought the car in February but it wasn't this bad it happens when I accelerate from a stop and when high rpm shifts are made. at first i thought it was the normal m3 diff clunk but eventually it got to the point where when i made high rpm shifts or accelerated fast it felt light someone was hitting the underbody of my car with a hammer ( a big hammer) now im just afraid of driving hard or even gong any higher than S1 on my SMG its been like this for a while and this morning i decided to check if it was the rear diff bushings so i lifted the back end and tried ti see if the diff had any movement and it turns out they are still good there wasn't any movement with the diff also the subframe bushings are good as well and so is the Guibi or whatever u call it the rubber spacer between the driveshaft and the Diff. so i guess my question is:

1. Where else is the sound coming from it feels like mid to rear clunk.

2. Could it be the Driveshaft center support? :dunno:

3. i need to fix this please help :(



I get the exact thing on mine under hard acceleration. If I lift my foot off the pedal when it shifts, it doesn't do it.

I had my car looked at in a dealership and they found that the shafts were loose in the diff. Everything else is still very solid. (bushings in front and behind the diff, tower mounts, subframe, etc.) My problem is the diff and shafts. That, at the dealership is a $5000 repair.

BlackStarMiG 11-11-2011 09:55 PM

yea same here if i let off the pedal right before it shifts it doesn't do it. so did you get it done? did it fix the problem?

Matt P. 11-12-2011 03:46 AM

I haven't done anything yet. It is in storage for the winter. I will try and find a used diff over the course of winter because $5000 is way too much. Or I might have this one rebuilt. There is a shop that specializes in diff reconstruction not too far from where I live. I will have them look at it before I do anything.

I don't know about your diff, but mine is leaking slightly too.



EDIT: I just noticed where you are from. I bought my car in Scottsdale. North Scottsdale BMW did the inspection and completely missed that.

BlackStarMiG 11-12-2011 08:23 PM

yea here in scottsdale there a chappman bmw thats where i buy my oil and all but im afraid to take it to get it inspected and have it come out with something else that didnt fix the problem and cost me an eye. i mean my diff feels good the car is really fast doesnt feel like something is wrong with it other than that loud bang i guess the best thing i could do is take it and see what they come up with

2004M3JMF 11-13-2011 01:15 AM

Yes, mine does the same thing. My diff is leaking a little too. Again, if I lift a little when shifting it doesn't do it. I would also like to know what the cause of this is. Maybe a mileage thing. I have 70k. Does anyone have the same issue with low mileage leads than 20k?

Matt P. 11-14-2011 04:52 AM

Quote:

Originally Posted by BlackStarMiG (Post 6437788)
yea here in scottsdale there a chappman bmw thats where i buy my oil and all but im afraid to take it to get it inspected and have it come out with something else that didnt fix the problem and cost me an eye. i mean my diff feels good the car is really fast doesnt feel like something is wrong with it other than that loud bang i guess the best thing i could do is take it and see what they come up with


My diff feels fine as well. There's no loose feeling when I turn corners. There's no wandering on the highway. The car is as fast as can be. It can spin the tires up and into 3rd gear. But when I give it a go, like you said it thumps so loud that it feels like the rear end will shear off.



Quote:

Originally Posted by 2004M3JMF (Post 6437972)
Yes, mine does the same thing. My diff is leaking a little too. Again, if I lift a little when shifting it doesn't do it. I would also like to know what the cause of this is. Maybe a mileage thing. I have 70k. Does anyone have the same issue with low mileage leads than 20k?

I have 97k on mine now. I don't know the previous owners driving habits either. Are all these cars from southern states where it is hot year round? I did notice that in Arizona, it was practically impossible to to make the rear tires spin on the hot pavement. Maybe the extra grip causes (premature?) wear on the diff and drivetrain?

BlackStarMiG 11-14-2011 03:16 PM

i didn't notice any oil leaking and yea mine pretty much burns out up to 3rd gear as well and i have 9+ inches of rear tire with my IForge rims, i dont think its the extra grip that does it, but thats the thing i just dont know what it can be that makes such a loud thump or bang sound i mean you feel it hit pretty hard in the underbody or somewhere and when i lifted the car the Diff looked and felt really solid no play at all i even tried moving it with a crowbar and some leverage but nope no play at all. my other option or thought was that it could be the shaft center support that might be worn so it could have some kind of play in the shaft and when you give it power or shift it could bump but idk since it was covered up by the heat shield

BlackStarMiG 11-14-2011 03:23 PM

I'm going to lift it up again and inspect it pretty thoroughly to see if i find something i didnt before ill let you guys know what happens

WE90325 11-20-2011 04:08 PM

I am buying a 2004 M3 with 99,000 miles. The owner said he replaced the diff fluid with Royal Purple fluid which does not have a friction modifier. He said he had it for a few months like that and before I purchased the car he would drain it and put in the OEM fluid?

Do you think this would have any negative effect or have destroyed anything?

BlackStarMiG 11-20-2011 09:31 PM

Quote:

Originally Posted by WE90325 (Post 6452798)
I am buying a 2004 M3 with 99,000 miles. The owner said he replaced the diff fluid with Royal Purple fluid which does not have a friction modifier. He said he had it for a few months like that and before I purchased the car he would drain it and put in the OEM fluid?

Do you think this would have any negative effect or have destroyed anything?


Its like they say the M devision spent tons and tons of money labor and science making these cars. I wouldn't put any other fluid other than what it is suppose to have. other ppl say royal purple works for them but i would just feel safer with the OEM fluid. just sayin...

Knight of HB 11-20-2011 10:00 PM

I've dealt with this complaint on three occasions on E46s that I can remember. Two ended up needing the diff bushing replaced, and one had a cracked rear subframe. The diff bushing cars were both automatics and clunked whenever you shifted between park, reverse or drive. The cracked rear subframe vehicle was a manual and was terrifying to drive. It made loud noises every time you shifted gears, sounded like the rear end of the car was going to fall off.

A damaged subframe should be fairly easy to spot if the vehicle's up on a lift.

BlackStarMiG 11-21-2011 05:23 PM

Quote:

Originally Posted by Knight of HB (Post 6453319)
I've dealt with this complaint on three occasions on E46s that I can remember. Two ended up needing the diff bushing replaced, and one had a cracked rear subframe. The diff bushing cars were both automatics and clunked whenever you shifted between park, reverse or drive. The cracked rear subframe vehicle was a manual and was terrifying to drive. It made loud noises every time you shifted gears, sounded like the rear end of the car was going to fall off.

A damaged subframe should be fairly easy to spot if the vehicle's up on a lift.


when i checked mine the bushings looked good

i have to check if its the subframe but how do you repair that?

Pinecone 11-22-2011 08:23 AM

Turner Motorsport has a kit to fix/prevent the subframe mount issues.

But it is a weld in kit and requires some skill to install.

Knight of HB 11-23-2011 02:53 PM

Quote:

Originally Posted by BlackStarMiG (Post 6454856)
when i checked mine the bushings looked good

i have to check if its the subframe but how do you repair that?

The one we did had to have the whole subframe replaced. However, it was pretty badly damaged; it had two very large cracks on both sides.

golferken55 12-05-2011 12:18 PM

wow thanks guys. I was just about to post a question but I think I found the answer. I hear a "thud" after shifting into gear and releasing clutch. I think its the differential but I dont hear anything though as been described. What does "wandering " mean?

Matt P. 12-05-2011 05:34 PM

I recently spoke to one of my technical advisors from a high performance shop I usually bring my other cars to and he said the thump we hear would be "normal". He said the system as it is will feel like the whole rear end wants to rip right off the back. Also said that the car may feel like it wants to break itself in half. We'll see, I have plans on getting that thoroughly checked out in the spring. Possibly even change the diff.

Pinecone 12-06-2011 07:07 AM

Quote:

Originally Posted by Matt P. (Post 6482178)
I recently spoke to one of my technical advisors from a high performance shop I usually bring my other cars to and he said the thump we hear would be "normal". He said the system as it is will feel like the whole rear end wants to rip right off the back. Also said that the car may feel like it wants to break itself in half. We'll see, I have plans on getting that thoroughly checked out in the spring. Possibly even change the diff.

Uh, NO.

BlackStarMiG 01-05-2012 12:05 AM

Any new News??? i wanna see if we can bring this thread back to life im still having the problem and im just getting more and more scared one day ill look in the rearview and see my diff on the ground :yikes::eek: and now i hear that the vanos bolts are crap and they sheer off potentially killing your engine wtf? i swear i have nightmares :bawling: why are e46 full of problems all of a sudden thi has always been one of my dream cars now i kind of regret having it :mad::cry:

BlackStarMiG 01-05-2012 12:13 AM

also before i forget since i live in arizona its always hot here but recently its been pretty cold well to us arizonians 57 degrees is cold. and when i start my car in the morning and switch to auto on the SMG on S1 it will not shift from 1st gear to 2nd till like 5k rpm or unless i switch to paddles but after a few gear changes i go back to auto and its fine. dont tell me my trans is gone now too ill shoot my self. any comments??

golferken55 01-05-2012 07:42 AM

Hey I ma having same issue with my e46. It soiunds "clunky" on occassion like rear diff is going to fall off. Also, do have trouble getting into low gears when accelerating slowly? It jumps and sloiws and jumps and slows like its noit in the gears right?? Thanks

Matt P. 01-05-2012 09:28 AM

Quote:

Originally Posted by Pinecone (Post 6483019)
Quote:

Originally Posted by Matt P. (Post 6482178)
I recently spoke to one of my technical advisors from a high performance shop I usually bring my other cars to and he said the thump we hear would be "normal". He said the system as it is will feel like the whole rear end wants to rip right off the back. Also said that the car may feel like it wants to break itself in half. We'll see, I have plans on getting that thoroughly checked out in the spring. Possibly even change the diff.

Uh, NO.


That's me being sceptical.

Right now my car is nicely tucked away, sound asleep in a garage next to an '86 Toyota 4Runner rock crawler. The more I think of it, the more I just want a "new" diff to end the problems. My frame is not damaged. I have the Turner Motorsports reinforcement kit to install no matter what to strengthen it.

Matt P. 01-05-2012 09:47 AM

Just so I can understand, I have seen different displays for the transmission on the dash. Mine doesn't look like what I have seen.

Here are some pictures of it. Sorry about the poor quality... they were taken with a cell phone... the ex took my camera. :mad:


Neutral...
http://i938.photobucket.com/albums/a...n/IMG00236.jpg



Auto mode... with a large D and a small S?

http://i938.photobucket.com/albums/a...n/IMG00235.jpg



Manual... Little D and no S??

http://i938.photobucket.com/albums/a...n/IMG00234.jpg




So far, does this all look normal to you all? Is it what you have?



This is one I found on google image... NOTHING like mine...

http://img.photobucket.com/albums/06...s/P1000380.jpg



The thread where I found the picture said O are early model and N are later models. Sounds reasonable. But I don't understand the large D and little S in Auto mode and only the little D in manual. Do you guys have anything different?




This is where I found the picture.
http://www.cslregister.com/forum/showthread.php?t=7564

They also talk about abrupt gear changes on the second page with a program upgrade to make the changes smoother. (at full throttle with foot buried in the carpet)

Pinecone 01-06-2012 06:33 AM

The little letter to the right of the neutral or 0 position tells you that moving the stick in that direction changes the mode to that mode.

The display is two parts. The left part is the Gear Number Indicator. The right part is a s shift diagram (like you find on shift knobs). But since what happens when you move the shift lever to the right changes, the letter on the shift diagram also changes.

In the early cars, S is sequential manual mode (only shifts when you tell it via the paddles), A is auto mode (shifts when it thinks it should).

A Big A next to the gear number tells you it is in Auto Mode. No letter next to the gear number means you are in S mode.

Pinecone 01-06-2012 06:35 AM

Quote:

Originally Posted by Matt P. (Post 6543093)
That's me being sceptical.

Right now my car is nicely tucked away, sound asleep in a garage next to an '86 Toyota 4Runner rock crawler. The more I think of it, the more I just want a "new" diff to end the problems. My frame is not damaged. I have the Turner Motorsports reinforcement kit to install no matter what to strengthen it.

It may not be the diff.

But my point was that ths is NOT normal.

I was saying that this part:

Quote:

..one of my technical advisors from a high performance shop I usually bring my other cars to and he said the thump we hear would be "normal". He said the system as it is will feel like the whole rear end wants to rip right off the back. Also said that the car may feel like it wants to break itself in half.
was NOT correct.


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