E46 Gear Change Clunk
Discussion
4rephill said:
Although it's not going to solve the annoyance of the clunk, at least you know it's not just your car that does it!
Try engaging 1st when the car is rolling very, very slowly forward and see if it still does it, I would be very interested in the result.
As I've previously posted, Mine doesn't clunk in those circumstances but does when 1st is engaged and the car is completely stationary. It's almost as if there is some "drive slack" being taken up when 1st gear is engaged stationary, that has already been taken up when the car is rolling forward.
This is what makes Me suspect the gearbox. When the car is stationary, and out of gear, there are no moving parts in the drive-train after the gearbox, and when 1st gear is engaged with the clutch depressed, there is still no movement in the drive-train after the gearbox until the clutch is released. As we know though, the clunk occurs at the exact moment that 1st gear is engaged, not when the clutch is released.
I'll have a look into if Mine clunks when engaging any other gear from a standstill (I'm pretty sure it doesn't but it's been quite a while since I last experimented with the clunk. At least your post has re-ignited My curiosity about the clunk issue if nothing else!
). *
My monies on it being the crank sensor playing up, but it could just as easily be a broken coil, plug, camshaft sensor. She goes to BMW Tuesday to be checked, but I'll be sure to post My experiment results here when she's working properly again. (Bloody car!
)
I will try the slow rolling forward test as you described.Try engaging 1st when the car is rolling very, very slowly forward and see if it still does it, I would be very interested in the result.
As I've previously posted, Mine doesn't clunk in those circumstances but does when 1st is engaged and the car is completely stationary. It's almost as if there is some "drive slack" being taken up when 1st gear is engaged stationary, that has already been taken up when the car is rolling forward.
This is what makes Me suspect the gearbox. When the car is stationary, and out of gear, there are no moving parts in the drive-train after the gearbox, and when 1st gear is engaged with the clutch depressed, there is still no movement in the drive-train after the gearbox until the clutch is released. As we know though, the clunk occurs at the exact moment that 1st gear is engaged, not when the clutch is released.
I'll have a look into if Mine clunks when engaging any other gear from a standstill (I'm pretty sure it doesn't but it's been quite a while since I last experimented with the clunk. At least your post has re-ignited My curiosity about the clunk issue if nothing else!
). *- * This experiment will have to wait until after I get the car running properly again though as she's miss-firing like a b
h at the moment!
My monies on it being the crank sensor playing up, but it could just as easily be a broken coil, plug, camshaft sensor. She goes to BMW Tuesday to be checked, but I'll be sure to post My experiment results here when she's working properly again. (Bloody car!
)Yes mine does "thump" when engaging other gears from standstill although to a lesser extent than selecting first. Of course there is no thump when chamging down!
I've noticed it does not do it when I first start off, i.e. when the car has being standing overnight etc. but after it has had a short run and stop/starts from thereon.
As you describe the noise is exactly when 1st gear is selected and the clutch depressed. Keep the clutch depressed when at standstill, in neutral and with the handbrake on and the thump does not happen when 1st is engaged - A cure? but still does not get rid of the 1st to 2nd clunk.
Interestingly when I was with the BMW Technician the other week and carrying out the stationary 1st gear issue the thump on occasion was that "violent" I could feel it through the seat!
Hope your car-cum-hovercraft is well soon
4rephill said:
To follow up on My previous post above:
(NOTE: The clunk that is heard/felt occurs when the car is completely stationary, either from being parked or completely at a complete stop in traffic. It is not a drive-train shunt or caused when the clutch is engaged - the clutch is fully depressed at the time of the clunk and the clunk occurs as the gear lever is moved to select the gear).
1) If I start off by reversing out of a space, completely stop the car and then engage 1st gear, I occasionally get a clunk but more often there is no clunk.
2) If I start off by engaging 1st gear, most times I get a clunk (not always though which is a bit baffling!), and the clunk is more pronounced than that experienced in example 1) above.
3) If I select another gear first (for example 3rd gear), and then go to 1st gear, there is no clunk going into 1st - but there may be a slight clunk going into the initial gear selected (3rd gear gear in this example). Again, this clunk seems to be less pronounced than the 1st gear clunk would be.
4) If I select 1st gear and get the clunk, immediately take the car out of 1st gear (with the clutch still depressed at all times), and then select 1st gear again - there is no clunk when 1st is re-selected. (The same thing happens if I select any other gear and then 1st without releasing the clutch).
5) If the car has only just become stationary and 1st gear is selected immediately - there is no clunk.
6) The clunk does occur when other gears are selected when the car is stationary but 1st gear is the most pronounced. (3rd seems to be the next worse, followed by 2nd, then 4th. 5th didn't seem to clunk at all).
7) As stated before, if the car is rolling even slightly forward then there is no clunk.
Based on My own findings (and the fact that auto's don't have this clunk issue), I'm convinced it's something worn inside the gearbox.
Apart from 1) above I would say that is exactly the issues I experience.(NOTE: The clunk that is heard/felt occurs when the car is completely stationary, either from being parked or completely at a complete stop in traffic. It is not a drive-train shunt or caused when the clutch is engaged - the clutch is fully depressed at the time of the clunk and the clunk occurs as the gear lever is moved to select the gear).
1) If I start off by reversing out of a space, completely stop the car and then engage 1st gear, I occasionally get a clunk but more often there is no clunk.
2) If I start off by engaging 1st gear, most times I get a clunk (not always though which is a bit baffling!), and the clunk is more pronounced than that experienced in example 1) above.
3) If I select another gear first (for example 3rd gear), and then go to 1st gear, there is no clunk going into 1st - but there may be a slight clunk going into the initial gear selected (3rd gear gear in this example). Again, this clunk seems to be less pronounced than the 1st gear clunk would be.
4) If I select 1st gear and get the clunk, immediately take the car out of 1st gear (with the clutch still depressed at all times), and then select 1st gear again - there is no clunk when 1st is re-selected. (The same thing happens if I select any other gear and then 1st without releasing the clutch).
5) If the car has only just become stationary and 1st gear is selected immediately - there is no clunk.
6) The clunk does occur when other gears are selected when the car is stationary but 1st gear is the most pronounced. (3rd seems to be the next worse, followed by 2nd, then 4th. 5th didn't seem to clunk at all).
7) As stated before, if the car is rolling even slightly forward then there is no clunk.
Based on My own findings (and the fact that auto's don't have this clunk issue), I'm convinced it's something worn inside the gearbox.
It is more baffling that the problem is not every single time 1st gear is engaged but "usual" rather than not.
Also nor forgetting the clunk when changing from 1st to 2nd which is constant.
Are diesel models also affected?
tonymor said:
Interesting reading I've had a clonking gear change as all of your postings on my zed 4 3.0si . BMW replaced the clutch and gearbox under warranty at 26000 miles it helped but not solved. My Indi serviced it last week and commented on it as being a bit too notchy , Ive reported the fault to Warranty Direct and my policy appears to accomodate gearbox problems .My trusted Indi had suggested firstly trying a gearbox oil additive but now I've followed this discussion ime inclined to leave"well" alone and follow the suggestions put foreward here. If I do go for the additive or gearbox out options I will update. I have to say I enjoy driving our golf gt Tdi as the gearbox is like a hot knife in HOT Butter.
That is interesting. Wonder if your Z4 3.0Si has the same gearbox as the E46.
Is the clunking mostly when changing 1st to 2nd and when standing and going into 1st?
I recently contacted BMW (UK) who in turn spoke with the dealer. This is their reply to me after speaking with the dealer;
"Upon receipt of your communication, I contacted Mr- -, Workshop Controller at - in -. Mr - has confirmed that initially the flywheel of your vehicle was replaced as this was though to be causing the noise you describe. However, you soon reported that the noise was still present.
Mr - then accompanied you on a test drive and determined that the noise is only apparent when the vehicle is sat idle and first gear is selected. This noise occurs when the drive train first becomes active. Mr - then tested this on other vehicles of a similar age to yours and found that the noise was present with them too. As a result, Mr - could only recommend that the noise is normal and that you monitor the noise".
1. I was not accompanied on a test drive. I demonstrated the noise sat in the car with the WC and explained the noise when driving and changing from 1st to 2nd gear
2. The noise is not only apparent when the vehicle is sat at idle (As 1 above)
3. Which vehicles of a similar age? I wasn't told that by the WC
4. If the noise is "normal" (after demonstrating to the WC how "violent" the noise at idle can be and feeling it through the seat) then all similar vehicles must suffer from it - Which they don't!
"Upon receipt of your communication, I contacted Mr- -, Workshop Controller at - in -. Mr - has confirmed that initially the flywheel of your vehicle was replaced as this was though to be causing the noise you describe. However, you soon reported that the noise was still present.
Mr - then accompanied you on a test drive and determined that the noise is only apparent when the vehicle is sat idle and first gear is selected. This noise occurs when the drive train first becomes active. Mr - then tested this on other vehicles of a similar age to yours and found that the noise was present with them too. As a result, Mr - could only recommend that the noise is normal and that you monitor the noise".
1. I was not accompanied on a test drive. I demonstrated the noise sat in the car with the WC and explained the noise when driving and changing from 1st to 2nd gear
2. The noise is not only apparent when the vehicle is sat at idle (As 1 above)
3. Which vehicles of a similar age? I wasn't told that by the WC
4. If the noise is "normal" (after demonstrating to the WC how "violent" the noise at idle can be and feeling it through the seat) then all similar vehicles must suffer from it - Which they don't!
4rephill said:
The version I got from My BMW Dealership was along the lines of:
"Some cars have the clunk, some cars don't, and the cause has never been found. We could replace items on the car to try and track down the issue, but to be honest, it won't make the car any more reliable and it could cost a lot of money. If you can live with it, save your money!"
(Be aware that I have known these guys for @ 25years and they look after Me very well! They could have easily gone down the "We need to replace parts" route and could have had a shed load of money off Me, but they were honest enough to advise Me that it wasn't worth going down that route really).
As my vehicle is still under AUC Warranty it's best anything that may be replaced is done now rather than the potential large expense once the car is out of warranty."Some cars have the clunk, some cars don't, and the cause has never been found. We could replace items on the car to try and track down the issue, but to be honest, it won't make the car any more reliable and it could cost a lot of money. If you can live with it, save your money!"
(Be aware that I have known these guys for @ 25years and they look after Me very well! They could have easily gone down the "We need to replace parts" route and could have had a shed load of money off Me, but they were honest enough to advise Me that it wasn't worth going down that route really).
I appreciate (and the odds are probably against) that the issue probably won't be resolved and I'll have to live with it but at this time there's nothing to loose trying
Found this on another forum.
I know that the M3 suffers from (quite commonly) the thumping issue.
I'm certainly not mechanically minded enough to know if this is the cause and the M3 diff and mechanicals etc would be completely different to my 320.
"E46 M3 - "Clunk Noise" on Load Reversal MODEL
E46 M3 with S54 engine SITUATION
Customer may complain of a drivetrain rattle or knocking noise during a load change, e.g. 1st to 2nd gearshift at low engine speed, coming from the rear axle area. Further drivetrain checks reveal that the right side rear axle output flange appears to have more play (approximately 0.5mm to almost 1mm) when compared to the left side output flange. INFORMATION
The radial play on the right side rear axle flange is a normal design characteristic of the new M differential lock style rear axle used on E46 M3 models. Therefore an M3 differential should not be replaced due to a difference in play (when comparing left to right side differential output flange play) since this will not eliminate a drivetrain rattle or knocking noise. IMPORTANT
In order to transmit engine torque to the rear wheels instantaneously, without any time lag, the whole M3 power train was designed with maximum torsional rigidity. Consequently, the flywheel mass and its damping capability has been reduced to a minimum. As a result, during an abrupt torque transfer (e.g. 1st to 2nd gearshift at low engine speeds) driver receives an acoustic feedback, which can be interpreted as a "clunking or rattling" noise. This characteristic is common in many high performance vehicles. Activation of the "Sport Mode" offers an additional increase in driving dynamics. As a result, acoustic feedback from the power train may be even more pronounced. The acoustic feedback characteristic is not a symptom of a failure, and does not compromise long-term reliability of drivetrain components (clutch, transmission, differential), nor does it adversely affect performance of the vehicle. WARRANTY INFORMATION"
I know that the M3 suffers from (quite commonly) the thumping issue.
I'm certainly not mechanically minded enough to know if this is the cause and the M3 diff and mechanicals etc would be completely different to my 320.
"E46 M3 - "Clunk Noise" on Load Reversal MODEL
E46 M3 with S54 engine SITUATION
Customer may complain of a drivetrain rattle or knocking noise during a load change, e.g. 1st to 2nd gearshift at low engine speed, coming from the rear axle area. Further drivetrain checks reveal that the right side rear axle output flange appears to have more play (approximately 0.5mm to almost 1mm) when compared to the left side output flange. INFORMATION
The radial play on the right side rear axle flange is a normal design characteristic of the new M differential lock style rear axle used on E46 M3 models. Therefore an M3 differential should not be replaced due to a difference in play (when comparing left to right side differential output flange play) since this will not eliminate a drivetrain rattle or knocking noise. IMPORTANT
In order to transmit engine torque to the rear wheels instantaneously, without any time lag, the whole M3 power train was designed with maximum torsional rigidity. Consequently, the flywheel mass and its damping capability has been reduced to a minimum. As a result, during an abrupt torque transfer (e.g. 1st to 2nd gearshift at low engine speeds) driver receives an acoustic feedback, which can be interpreted as a "clunking or rattling" noise. This characteristic is common in many high performance vehicles. Activation of the "Sport Mode" offers an additional increase in driving dynamics. As a result, acoustic feedback from the power train may be even more pronounced. The acoustic feedback characteristic is not a symptom of a failure, and does not compromise long-term reliability of drivetrain components (clutch, transmission, differential), nor does it adversely affect performance of the vehicle. WARRANTY INFORMATION"
buggalugs said:
I'm sure on my car now that the clunk when engaging 1st is coming from the rearmost UJ in the propshaft. I managed to get a video of it, here I was just twisting the prop at the gearbox end with one hand whilst filming the joint with the other. You can imagine that with friction or inertia turning the gearbox with any kind of speed or force the clunk would be that much more violent.
One thing's for sure, I need a new prop, and sooner rather than later!
http://youtu.be/cfFndio2hck?hd=1
What vehicle is your clunk on?One thing's for sure, I need a new prop, and sooner rather than later!
http://youtu.be/cfFndio2hck?hd=1
Has it worsened over time?
buggalugs said:
E46 328i Manual
I would say yes
A bit disconcerting that you say the symptoms have worsened. Then again I don't know the exact symptoms you have, if they are the same as I have, how long you've had them etc.I would say yes
I've noticed mine now clunks when engaging reverse from standstill and 1st to 4th gears. Nothing when the clutch is depressed all of the time.
I have a letter published in this months BMW Car mag outlining the issue. They asked a BMW specialist (BM Sport) who stated the thump is general play in the drivetrain and is worse in some cars than others (I still wonder why that is) Also suggested changing the gearbox oil and have the hydraulic system bled.
dr_gn said:
Absolutely not technique - I can get the clunk when stationary just by putting it into first/reverse. Apart from not knowing what a clutch is, there's no technique there!
Absolutely. The clunk is there when the car is stationary. However, keeping the clutch depressed and changing gears lessens the clunk or if changing into first (whilst stationary) very slowly then the clunk is almost non existant. But as I reasoned with the BMW tech why should changing "driving style" have to be adopted to lessen the issue? It would not be normal practice when staionary to keep the clutch permanently depressed or change gear as if in slow motion - Therefore trying to overcome the mechanical issue!
buggalugs said:
I changed the propshaft, flex coupling and centre bearing last weekend. My drive is much smoother & quieter cause the old prop was fked. The clunk is a little bit better but still there.
The remaining drivetrain lash is in the rear half shafts, one side seems to be mostly the inboard CV joint and one side mostly the outboard.
I might change the shafts if I have to do a wheel bearing or something but otherwise I'm just going to live with it.
Would be interesting to see if the clunk was still present should you change the other shafts - although would prove to be somewhat costly and without any guarantee that the issue was sorted.ked. The clunk is a little bit better but still there. The remaining drivetrain lash is in the rear half shafts, one side seems to be mostly the inboard CV joint and one side mostly the outboard.
I might change the shafts if I have to do a wheel bearing or something but otherwise I'm just going to live with it.
For the last few days........ No clunk! Try as I did today engaging first from standstill - Nothing! Seems to have mysteriously cured itself (fingers crossed) Still a bit of a noise from first to second but nothing like it was. Maybe the replacement clutch and flywheel have "settled in" or a few more thousand miles on the clock has helped.
Whatever the reason it appears sorted - hopefully for good.
Whatever the reason it appears sorted - hopefully for good.
Ritchie335is said:
The clunk that is heard when you slot it into gear is all of the play in the drivetrain being taken up. Which there is not much you can do about apart from replacing the propshaft, diff and driveshafts.
You have a little play in the diff, both inner joints and both outer joints plus whatever wear is on the propshaft (if any), a shaft has to be well fooked before there is play in the joints and I have never seen a BMW joint worn yet, although I'm not saying it doesn't happen.
The reason you are not hearing it when it is colder, is that the gearbox oil is thicker which dampens the jolt through the shaft when you put it into gear, hence it's back to normal when it warms up.
Also the knock is reduced when you engage a gear while rolling down a hill as the shafts are already rotating and there is a smaller speed differential minimising the shock.
Two things which might help are fresh gear and diff oil if the the original stuff is a bit thin and tired and holding the clutch in for a few seconds before engaging gear.
This should allow the first motion shaft to slow down as the friction plate will act like a flywheel to keep it spinning, although this depends on how much the clutch is dragging when disengaged.
Thats my opinion anyway.
Your clear explanation certainly helps me understand the mechanics of the issue.You have a little play in the diff, both inner joints and both outer joints plus whatever wear is on the propshaft (if any), a shaft has to be well fooked before there is play in the joints and I have never seen a BMW joint worn yet, although I'm not saying it doesn't happen.
The reason you are not hearing it when it is colder, is that the gearbox oil is thicker which dampens the jolt through the shaft when you put it into gear, hence it's back to normal when it warms up.
Also the knock is reduced when you engage a gear while rolling down a hill as the shafts are already rotating and there is a smaller speed differential minimising the shock.
Two things which might help are fresh gear and diff oil if the the original stuff is a bit thin and tired and holding the clutch in for a few seconds before engaging gear.
This should allow the first motion shaft to slow down as the friction plate will act like a flywheel to keep it spinning, although this depends on how much the clutch is dragging when disengaged.
Thats my opinion anyway.
Edited by Ritchie335is on Monday 5th November 23:43
However, why is the play more noticeable in my (and others) vehicle?. I've never had it with any other vehicle I have owned - BMW, non BMW or any other vehicle I have driven. I question whether it is a design fault or poor engineering!
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