BimmerFest BMW Forum banner
1 - 20 of 26 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter · #1 ·
I have a 2002 325xi that is only a few weeks old and has about 800 miles on it. When I shift gears, especially from 1st to 2nd and from 2nd to 3rd, I sometimes hear a "thunk" or "clunk" when I engage the clutch. The sound is like the transmission has a bit of "freeplay" in the gears and when engaging the clutch, this process quickly takes up the slack, causing this sound. There is a slight jar when this happens.

I notice that generally if I rev match (within 250 rpms) that this minimizes the number of incidents of this thunking. Also, on hills, the thunking does not seem to happen as often -- maybe the freeplay is taken up.

My BMW service center looked at the car this morning and told me that it was "normal for some cars" and that the M3 have a really loud clunking sound (I suppose I could live with that if I had an M3 . . . ).

1. Is this normal, or is it just my shifting technique (I have not had any trouble shifting). Could it be that for DBW I need to press the accelerator a fraction of a second before I start to engage the clutch?

2. What causes this?

3. Is it harmful to the transmission? (Service says no, wait to see if it gets worse.)

Note that I have driven a 330xi, a friend's new 325xi, and a 5 series car and none of them do this when I drive it.

Your comments and suggestions would be greatly appreciated.

TIA.

BTW, I have done a search on a number of boards, including this one, and have only found 1 thread that seem directly related to this problem.
 

·
Registered User
Joined
·
10,856 Posts
In my experience, I've only experienced a clunk when I screw up a shift. :dunno: Maybe you need to take a look at some of my CDV threads?
 

·
nature geek
Joined
·
69 Posts
It only happens for me too when I miss time a shift. It happens if I shift from 2nd to 3rd at low revs (2000rpm).

Sure does not sound or feel pleasant, but seems to be related to the Xis mostly.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #4 ·
Nick325xiT 5spd said:
In my experience, I've only experienced a clunk when I screw up a shift. :dunno: Maybe you need to take a look at some of my CDV threads?
Actually, I have been following the CDV threads very closely. The thing is that I drive my friend 325xi with only 750 miles on it (and so is just as new as mine) and his does not do this.
 

·
Registered
Joined
·
337 Posts
I get this on my car sometimes.

I get a clunk when the clutch is engaged, and then I shift it into gear. I was told it happens cause of excess backlash in the gears. If I were to hold the clutch down for a while, then put it into gear, it wouldnt happen. Im not 100% positive how the drivetrain works and stuff, so Im sure someone can better explain it
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #6 ·
CH_325xiT said:
It only happens for me too when I miss time a shift. It happens if I shift from 2nd to 3rd at low revs (2000rpm).

Sure does not sound or feel pleasant, but seems to be related to the Xis mostly.
What happens if you shift to 1st gear from a stop? If I shift to 1st from idle or around 1000 rpms, it will happen. Rev to 1500 to 2000 rpms to 1st and SLOWLY let out the clutch and there is a much reduced chance of this happening (but, it seems, a greater chance of wearing out the clutch).

My rpms also seem to drop fairly quickly thus, the way I shift now is to almost always keep some pressure on the accelerator (as opposed to completely taking my foot off when disengaging the clutch) and thus slowing the drop on rpms. I then engage with the gas still on.

How do you deal with it and is this technique a problem?
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #7 ·
chukiechz said:
I get this on my car sometimes.

I get a clunk when the clutch is engaged, and then I shift it into gear. I was told it happens cause of excess backlash in the gears. If I were to hold the clutch down for a while, then put it into gear, it wouldnt happen. Im not 100% positive how the drivetrain works and stuff, so Im sure someone can better explain it
Do you mean when you disengage the clutch and shift into a gear?
 

·
Registered
Joined
·
337 Posts
genaplex:
thanks for the idea, but I dont think its the synchros. It did it in my old getrag tranny and it still does it in the new zf tranny. the only things not replaced are the driveshaft and diff, so it's gotta be the diff.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #12 ·
genaplex said:
Engine mounts?

Justin
I do not think so since the noise is coming from the rear diff.

This car definately shifts differently than my previous Rabbit, Subaru and Honda (and is alot more fun to drive also). I am not sure if this is an artifact of DBW, hydraulic clutch, CDV, variations in the transmission manufacturing process, or some combination of those factors.
 

·
OMGWTFBBQ
Joined
·
11,262 Posts
bsm325xi said:
I do not think so since the noise is coming from the rear diff.
I've had since day one. When I get it, it always comes from the rear. It only seems to happen at very low revs, ie at a stop, putting it into first from neutral. I don't recall hearing it for the 1-2 or 2-3 shift. I've been thinking that it has something to do with clutch take up. If I'm extra smooth and slow with the clutch, it doesn't happen. If I'm quicker with it, but not launch with any real revs is when it happens.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #14 ·
Thanks to those who responded so far, you have been very helpful. Aside from the noise, it seems to make driving when shifting very abrupt because the car jerks forward alittle each time it thunks, although not what I would call "jerky".

Is this your driving experience also?

After reading your reponses, I also noticed that the thunk sometimes happens when I shift into gear -- syncros problem?

Thank you for your insights.
 

·
Registered
Joined
·
43 Posts
synchro problem is very common. Shift it gentaly... with around 0.5 sec pause from 1st to N then N to 2nd (instead of 1st to 2nd immediately). If that noise didn't comming again then that should be the synchro. I have heard some new mini have the same problem... see the curren mini review in edmunds.
 

·
Registered
Joined
·
138 Posts
i actually just noticed something similar the other day. I have a 2001 325xi with about 6000 miles on it. I noticed that when i am in stop and go traffic or at a stop light that there is a thunk when the clutch is depressed and i just row the stick through the gears: 1st, 2nd or even 3rd. Is this just a synchro problem, or some other underlying process?

I feel like i may have f'ed somethig up since this is my first stick-shift and i still get some jerky shifts once in a while. I'm going to try to take out that CDV one weekend because i notice that when i shift and don't depress the clutch fully (ie: depress the clutch just after it disengages from the gear i'm in) and then shift gears and let up the clutch, that i have much smoother, quicker and funner (word?:confused: ) shifts. Anyone else notice this?

[EDIT: after reading genaplex's comment more carefully, does anyone think my "learning" how to drive stick on this car may have destroyed the first gear synchro. I'll admit i have no idea what i'm talking about (mechanically) so i have very little reference.]
 

·
Here since day one
Joined
·
7,187 Posts
It might go away with time . . . sometimes parts need to break in.

If it were still happening at 3000 miles, I would have it checked again but there is a good chance this might go away by then.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #19 ·
Brought my car to Gearhart BMW in NJ for them to check out the car and give me a second opinion. They were very good about looking at the car and put the car on the lift, checked the drivetrain (by hand) for freeplay and checked the fluid levels. All were okay according to them. In addition, they said that it may be simply that it is AWD model and they tend to be noisier or that the car may be rocking a little back and forth when shifting.

Does this may any sense?

Of course, when I brought it in this morning, it was more difficult to replicate the problem and when it did thunk, it was faint. Wish it was just jerky, then I would know it was just me. Anyway, this appears to be most noticable if I am more than 250 rpm off the finally rpms for the shifted gear.

I will wait a few more thousand miles, but in the mean time, any other thoughts in addition the great advice already given would be appreciated. Thanks!
 

·
Registered
Joined
·
2 Posts
cluth impossible to navigate

I have (2) 2002 325xi's, one sedan, one wagon, both 5 speed, they both have less than 5000 miles on them. I have noticed that it is virtually impossible to get into 1st or second gear without the car either thunking and lurching forward or stalling or near stalling. I have has the dealer and factory rep look at the cars and they are recommending clutch replacements. I have noticed that many people have been complaining about the uneven and sloppy clutch function and that coupled with a long shift throw and AWD, the cars are virtually impossible to drive without either lunging forward, stalling or generally looking like an amateur when you drive. I am looking to BMW to resolve these issues, I would appreciate all affected BMW owners to contact me at [email protected] so that we can approach BMW once about this and get some resolution. I have been driving stick for 25 years and have owned at least 10 BMW's and other 5 speed and have never experienced anything of this nature with any vehicle. I consider this to be a factory flaw and/or a mis-engineered defect. Again, I would appreciate anyone with similar clutch, shifting and or 5 speed problems to contact me at: [email protected]
 
1 - 20 of 26 Posts
Top