[68FB]

Deleted.

 

[mattmor]

Are you having any shifting or clutch-related problems other than the vibration/noise?

 

[goodmaj]

Not really. There's the usual tightness, particularly in 2nd, when the car is ice cold, and the shifter is notchy through 4th gear, but it's not like it's getting stuck in gear or grinding as the gears are changed. When the clutch was replaced over the summer they did not replace the flywheel as it was in good shape.

 

[mattmor]

Not really. There's the usual tightness, particularly in 2nd, when the car is ice cold, and the shifter is notchy through 4th gear, but it's not like it's getting stuck in gear or grinding as the gears are changed. When the clutch was replaced over the summer they did not replace the flywheel as it was in good shape.

I'm still wondering why the vibration is being felt through the shifter. This could be a longshot, but I want to throw this out at least. There is an example of occasional complaints concerning the transmission, clutch, engine or acoustics reported. In most of these cases, there were engine or transmission related repairs which resulted in missing or damaged dowels necessary for centering the engine/transmission (at least according to field investigations). The effect is that flush alignment of the flywheel with respect to the transmission input shaft/torque converter is no longer guaranteed. The following complaints can occur as a result:

- Clutch judder/poor disengagement
- Transmission input shaft produces noise
- Gears jump
- Snagging gearshift

 

[goodmaj]

Certainly good points. After the clutch was replaced, which was the last time anything was touched on the driveline, everything was fine. The problem cropped up a few months ago but before then no issues.

What I will say is sometimes when I use the clutch I hear a very soft pop or noise that tells me I've re-engaged or disengaged the clutch. For example, say I'm at around 3.5K RPMs and am in 2nd. I engage the clutch and might get a small noise that tells me the clutch has disengaged from the flywheel. I shift into 3rd and might hear a slightly different noise that lets me know I've engaged the clutch. It doesn't happen all the time but I'll try to take a video of it this weekend or early next week.

I will also say that on rare occasion I've found myself slightly "drifting" when putting the car into gear. This usually happens when going into 3rd or 4th. It doesn't go straight in or notchy in, rather it almost seems like something's loose. I find myself ever so slightly adjusting the shifter on the way in when I feel this happen and life goes on. I want to emphasize this is a pretty rare occurrence but it has happened maybe 10-15 times in the year+ I've owned the car. The gearshift has never gotten stuck on the way out of a gear though.

Indy #1 mentioned the dowels as well. When I told them that Indy #2 were the ones who did the clutch, their reaction was "ok, those guys know what they're doing" or similar. Plus, this problem didn't start until a few months after I had the clutch replaced.

But, one thing I was wondering, and my limited transmission/driveline knowledge is coming into play so please excuse me if I'm just way off base. If the springs in the flywheel are toast, wouldn't this result in the flywheel having excess movement as it spins either in gear or otherwise? The con to this theory is that the centrifugal force generated by spinning would "lock" the flywheel into a certain position only to be unlocked when the revs went down. Just total, possibly completely off base, speculation.

 

[psyb0rg]

My car has a similar vibration. I just noticed it today while driving with my hand on the shifter on the freeway. I don't hear any weird noises and the vibration frequency seems to be constant. But in my case, one of the oil filter mounts is broken, wheel alignment is slightly off, the transmission and diff oils have never been changed on the car and there is a metallic rattle under the car when you close a door, which sounds like some worn exhaust bushings. :grinyes:

I'm addressing these one by one and will let you know if anything makes a difference.

 

[mattmor]

Certainly good points. After the clutch was replaced, which was the last time anything was touched on the driveline, everything was fine. The problem cropped up a few months ago but before then no issues.

What I will say is sometimes when I use the clutch I hear a very soft pop or noise that tells me I've re-engaged or disengaged the clutch. For example, say I'm at around 3.5K RPMs and am in 2nd. I engage the clutch and might get a small noise that tells me the clutch has disengaged from the flywheel. I shift into 3rd and might hear a slightly different noise that lets me know I've engaged the clutch. It doesn't happen all the time but I'll try to take a video of it this weekend or early next week.

You might check the pedal travel under the dash to make sure that soft popping noise isn't just the clutch pedal arm grazing something while it travels to and from the floor. It happens.

I will also say that on rare occasion I've found myself slightly "drifting" when putting the car into gear. This usually happens when going into 3rd or 4th. It doesn't go straight in or notchy in, rather it almost seems like something's loose. I find myself ever so slightly adjusting the shifter on the way in when I feel this happen and life goes on. I want to emphasize this is a pretty rare occurrence but it has happened maybe 10-15 times in the year+ I've owned the car. The gearshift has never gotten stuck on the way out of a gear though.

Did you change the plastic shift lever bearing when you put the F10 in? If you didn't, then it could be worn which causes play during shifting.

Indy #1 mentioned the dowels as well. When I told them that Indy #2 were the ones who did the clutch, their reaction was "ok, those guys know what they're doing" or similar. Plus, this problem didn't start until a few months after I had the clutch replaced.

Everyone makes mistakes and sometimes they don't always show up right away

But, one thing I was wondering, and my limited transmission/driveline knowledge is coming into play so please excuse me if I'm just way off base. If the springs in the flywheel are toast, wouldn't this result in the flywheel having excess movement as it spins either in gear or otherwise? The con to this theory is that the centrifugal force generated by spinning would "lock" the flywheel into a certain position only to be unlocked when the revs went down. Just total, possibly completely off base, speculation.

Normally, the mass of the flywheel maintains a constant angular velocity which resists torque variations in the engine. The moment of inertia is a scalar function as long as there is a fixed axis. If the flywheel no longer remains on a fixed axis, then you introduce an inertia matrix which has the characteristic of increased precession forces and fretting. Then the flywheel will no longer resist torque variations from the engine as it would with a constant angular velocity. It also wears out a lot faster.

 

[ger]

The vibrations seem to be engine speed related, occurring at 2000rpm and older or more pronounced under greater load. You've checked the oil filter and ps reservoir mounts, bracket and piping, all seem good. I would still squash a rag behind them and go for a short drive, just to eliminate them.

I'd also check the undertrays. These have been disturbed and may not have been refitted properly. You could try the car without the undertrays.

The engine is a big lump. It will move (relatively slowly) in relation to the overall torque given out, so it tries to twist itself against the chassis, through its four mounts. Whilst under this torque, the engine will also 'pulse' or vibrate due to the detonations in each cylinder at a rate of four per crank revolution (yup it's a v8, but 4stroke, so for all eight cylinders to fire takes two crank revolutions, presuming they're evenly 'spaced').

The two frontmost mounts resist most of the torque and take the larger proportion of the engine's weight and absorb much of the 'pulsing'.

As a matter of maintenance I'd have these two replaced, they're not very expensive and are easy to change, they only have three nuts to remove! On mine, the left hand mount had certainly seen better days and I'm sure the car was considerably smoother after changing them.

The rear, transmission mounts do some work too and since these were disturbed to change the clutch, I'd just change them as well, they're cheap and again quite easy to change. On one of mine, iirc, the rubber had completely separated from the steel flange to which it was meant to be attached.

I'd consider the four engine mounts as normal maintenance and little money spent well and wisely.

Further down the line, the slowly 'twisting under load' and pulsing of the engine will affect other components, mostly the exhaust. As has been mentioned the central exhaust mountings can and do deteriorate. Again a cheap and easy replacement that's not a bad idea.

Not mentioned yet, I think, are the exhaust brackets that are under the transmission, just forward of the transmission mounts (iirc). I'm pretty sure these would have been disturbed in the clutch job and worth inspecting to ensure all the nuts/bolts/spacers/rubber washers or bushings are all present and correctly tightened.

A general look under the car and over the whole exhaust, with an open mind regarding how much it can move, might be beneficial. Also, ensure that all heatshields are present and properly secured. Due to them being aluminium and held by steel nuts/washers and bolted to a steel body, sometimes they can corrode through and loosen (and therefore knock/vibrate). An usual fix is to use a large 'penny washer' to secure them again. I'm aware that some heatshields are also held by plastic hardware, not so sure how susceptible these would be regarding corroding the heatshield.

Thinking a bit more:
You have the crank spinning away (2k rpm, 1k detonations per minute-it's a 4stroke- so '16 and 2/3rd' detonations per second, so should be about 16 to 17Hz-you could set up a microphone and a portable oscilloscope and monitor the sound's frequency if you wanted!).

The transmission uses a dual mass flywheel. These were originally developed to reduce driveline vibrations at low rpm's (about 600rpm) in big diesel engines, as the vibrations gave the gears a really hard time.

They are used in petrol (gasoline) cars to further the refinement and reduce nvh levels, but aren't really necessary to protect transmissions (the springs in the clutch friction disc of a solid flywheel setup did a good enough job, apparently; so I understand).

They have the flywheel separated into two sections, lets say roughly half each, so one half is bolted to the crank and the other half can move a bit. It's held in place by a bearing of sorts, its rotation is resisted by relatively long springs (two usually, though I'm not sure on the m5 flywheel), these long springs allow quite a bit of rotation of one half compared to the other (lets say 25degrees for the sake of argument, I don't know what it actually is, dig for some technical info if its important!) and their strength would have been selected and 'tuned' for the car. To stop everything bouncing backwards and forwards, the two halves are damped by some means, I'm sure I've seen friction plates mentioned somewhere.

So, when a cylinder fires, it pulses the crank a bit (accelerating it for a very short time), then the crank coasts/slows down a bit until the next 'pulse' comes along and gives it another pulse. When the crank is pulsed, the springs compress and when the crank is coasting the springs expand; if done correctly all of this will allow the second flywheel half to move much more 'steadily' and smooth out much of the pulses.

In a slightly different way, all the dual mass flywheel does is absorb the single pulse and tries to distribute it more evenly between the pulses, smoothing the drive.

If anything in the flywheel is defective, it will affect how all of this works. A broken spring, worn friction plates and worn bearing all have their effects.

Now, after all of that, at 2k rpm I'm pretty sure the dual mass flywheel isn't meant to be doing much, well a fully functioning one at least. A defective one might well introduce problems and vibrations, I'm not sure what though.

The main problem is that to have it inspected means taking off the transmission, you might as well have it replaced if you're going back in there as well as the ream main seal (rms).

I'd change the engine and transmission mounts, check everything else thoroughly (myself or at least be present with the mechanic) and then if it persists, let it develop for a while, it may become blatantly obvious what is causing it without you having to spend a fortune.

If I've said anything incorrectly I'd welcome correction by anyone.
I hope somehow this helps.

 

[D-RodM5]

Jim, sorry about the troubles with the beast! I don't want to scare you, but do you, or does anyone else, hear a distinct "tink tink tink" sound in that last video from post #37? Maybe it's just the acoustics captured by the camera.


After reading post #48, bad engine and/or transmission mounts are a plausible culprit. However, given your mileage (71k+) I still posit that it may be a driveshaft/CB/guibo issue.


In any case, with all the inputs here and with your own process of elimination, at least you can make an educated guess to get this thing solved!

 

[goodmaj]

Jim, sorry about the troubles with the beast! I don't want to scare you, but do you, or does anyone else, hear a distinct "tink tink tink" sound in that last video from post #37? Maybe it's just the acoustics captured by the camera.


After reading post #48, bad engine and/or transmission mounts are a plausible culprit. However, given your mileage (71k+) I still posit that it may be a driveshaft/CB/guibo issue.


In any case, with all the inputs here and with your own process of elimination, at least you can make an educated guess to get this thing solved!

Tell me about it. Amazing what you'll do when your car is fully paid off.....

What tink tink tink are you referring to, and what's the downside of said tink tink tink? VANOS?

 

[goodmaj]

The vibrations seem to be engine speed related, occurring at 2000rpm and older or more pronounced under greater load. You've checked the oil filter and ps reservoir mounts, bracket and piping, all seem good. I would still squash a rag behind them and go for a short drive, just to eliminate them.

I'd also check the undertrays. These have been disturbed and may not have been refitted properly. You could try the car without the undertrays.

The engine is a big lump. It will move (relatively slowly) in relation to the overall torque given out, so it tries to twist itself against the chassis, through its four mounts. Whilst under this torque, the engine will also 'pulse' or vibrate due to the detonations in each cylinder at a rate of four per crank revolution (yup it's a v8, but 4stroke, so for all eight cylinders to fire takes two crank revolutions, presuming they're evenly 'spaced').

The two frontmost mounts resist most of the torque and take the larger proportion of the engine's weight and absorb much of the 'pulsing'.

As a matter of maintenance I'd have these two replaced, they're not very expensive and are easy to change, they only have three nuts to remove! On mine, the left hand mount had certainly seen better days and I'm sure the car was considerably smoother after changing them.

The rear, transmission mounts do some work too and since these were disturbed to change the clutch, I'd just change them as well, they're cheap and again quite easy to change. On one of mine, iirc, the rubber had completely separated from the steel flange to which it was meant to be attached.

I'd consider the four engine mounts as normal maintenance and little money spent well and wisely.

Further down the line, the slowly 'twisting under load' and pulsing of the engine will affect other components, mostly the exhaust. As has been mentioned the central exhaust mountings can and do deteriorate. Again a cheap and easy replacement that's not a bad idea.

Not mentioned yet, I think, are the exhaust brackets that are under the transmission, just forward of the transmission mounts (iirc). I'm pretty sure these would have been disturbed in the clutch job and worth inspecting to ensure all the nuts/bolts/spacers/rubber washers or bushings are all present and correctly tightened.

A general look under the car and over the whole exhaust, with an open mind regarding how much it can move, might be beneficial. Also, ensure that all heatshields are present and properly secured. Due to them being aluminium and held by steel nuts/washers and bolted to a steel body, sometimes they can corrode through and loosen (and therefore knock/vibrate). An usual fix is to use a large 'penny washer' to secure them again. I'm aware that some heatshields are also held by plastic hardware, not so sure how susceptible these would be regarding corroding the heatshield.

Thinking a bit more:
You have the crank spinning away (2k rpm, 1k detonations per minute-it's a 4stroke- so '16 and 2/3rd' detonations per second, so should be about 16 to 17Hz-you could set up a microphone and a portable oscilloscope and monitor the sound's frequency if you wanted!).

The transmission uses a dual mass flywheel. These were originally developed to reduce driveline vibrations at low rpm's (about 600rpm) in big diesel engines, as the vibrations gave the gears a really hard time.

They are used in petrol (gasoline) cars to further the refinement and reduce nvh levels, but aren't really necessary to protect transmissions (the springs in the clutch friction disc of a solid flywheel setup did a good enough job, apparently; so I understand).

They have the flywheel separated into two sections, lets say roughly half each, so one half is bolted to the crank and the other half can move a bit. It's held in place by a bearing of sorts, its rotation is resisted by relatively long springs (two usually, though I'm not sure on the m5 flywheel), these long springs allow quite a bit of rotation of one half compared to the other (lets say 25degrees for the sake of argument, I don't know what it actually is, dig for some technical info if its important!) and their strength would have been selected and 'tuned' for the car. To stop everything bouncing backwards and forwards, the two halves are damped by some means, I'm sure I've seen friction plates mentioned somewhere.

So, when a cylinder fires, it pulses the crank a bit (accelerating it for a very short time), then the crank coasts/slows down a bit until the next 'pulse' comes along and gives it another pulse. When the crank is pulsed, the springs compress and when the crank is coasting the springs expand; if done correctly all of this will allow the second flywheel half to move much more 'steadily' and smooth out much of the pulses.

In a slightly different way, all the dual mass flywheel does is absorb the single pulse and tries to distribute it more evenly between the pulses, smoothing the drive.

If anything in the flywheel is defective, it will affect how all of this works. A broken spring, worn friction plates and worn bearing all have their effects.

Now, after all of that, at 2k rpm I'm pretty sure the dual mass flywheel isn't meant to be doing much, well a fully functioning one at least. A defective one might well introduce problems and vibrations, I'm not sure what though.

The main problem is that to have it inspected means taking off the transmission, you might as well have it replaced if you're going back in there as well as the ream main seal (rms).

I'd change the engine and transmission mounts, check everything else thoroughly (myself or at least be present with the mechanic) and then if it persists, let it develop for a while, it may become blatantly obvious what is causing it without you having to spend a fortune.

If I've said anything incorrectly I'd welcome correction by anyone.
I hope somehow this helps.

Thanks Ger, this is a lot of good info. In fact, this entire thread is a boatload of good info and proves the point that this board is the best around.

At this point, next week the car is going back in for additional inspection. No one has mentioned transmission, so that's at least one bonus. The areas I'm going to ask them to focus on are the exhaust (for the whoom whoom resonating sound I'm getting in the same RPM band, particularly when cruising in that band in 3rd-6th), the exhaust mounts, the engine mounts, and the driveshaft/CB. Next up would be a removal of the transmission but let's start with the easier stuff now. I have an appt for Wednesday already. I'll probably pass on the transmission fluid change for now.

 

[68FB]

The vibrations seem to be engine speed related, occurring at 2000rpm and older or more pronounced under greater load. You've checked the oil filter and ps reservoir mounts, bracket and piping, all seem good. I would still squash a rag behind them and go for a short drive, just to eliminate them.

I'd also check the undertrays. These have been disturbed and may not have been refitted properly. You could try the car without the undertrays.

The engine is a big lump. It will move (relatively slowly) in relation to the overall torque given out, so it tries to twist itself against the chassis, through its four mounts. Whilst under this torque, the engine will also 'pulse' or vibrate due to the detonations in each cylinder at a rate of four per crank revolution (yup it's a v8, but 4stroke, so for all eight cylinders to fire takes two crank revolutions, presuming they're evenly 'spaced').

The two frontmost mounts resist most of the torque and take the larger proportion of the engine's weight and absorb much of the 'pulsing'.

As a matter of maintenance I'd have these two replaced, they're not very expensive and are easy to change, they only have three nuts to remove! On mine, the left hand mount had certainly seen better days and I'm sure the car was considerably smoother after changing them.

The rear, transmission mounts do some work too and since these were disturbed to change the clutch, I'd just change them as well, they're cheap and again quite easy to change. On one of mine, iirc, the rubber had completely separated from the steel flange to which it was meant to be attached.

I'd consider the four engine mounts as normal maintenance and little money spent well and wisely.

Further down the line, the slowly 'twisting under load' and pulsing of the engine will affect other components, mostly the exhaust. As has been mentioned the central exhaust mountings can and do deteriorate. Again a cheap and easy replacement that's not a bad idea.

Not mentioned yet, I think, are the exhaust brackets that are under the transmission, just forward of the transmission mounts (iirc). I'm pretty sure these would have been disturbed in the clutch job and worth inspecting to ensure all the nuts/bolts/spacers/rubber washers or bushings are all present and correctly tightened.

A general look under the car and over the whole exhaust, with an open mind regarding how much it can move, might be beneficial. Also, ensure that all heatshields are present and properly secured. Due to them being aluminium and held by steel nuts/washers and bolted to a steel body, sometimes they can corrode through and loosen (and therefore knock/vibrate). An usual fix is to use a large 'penny washer' to secure them again. I'm aware that some heatshields are also held by plastic hardware, not so sure how susceptible these would be regarding corroding the heatshield.

Thinking a bit more:
You have the crank spinning away (2k rpm, 1k detonations per minute-it's a 4stroke- so '16 and 2/3rd' detonations per second, so should be about 16 to 17Hz-you could set up a microphone and a portable oscilloscope and monitor the sound's frequency if you wanted!).

The transmission uses a dual mass flywheel. These were originally developed to reduce driveline vibrations at low rpm's (about 600rpm) in big diesel engines, as the vibrations gave the gears a really hard time.

They are used in petrol (gasoline) cars to further the refinement and reduce nvh levels, but aren't really necessary to protect transmissions (the springs in the clutch friction disc of a solid flywheel setup did a good enough job, apparently; so I understand).

They have the flywheel separated into two sections, lets say roughly half each, so one half is bolted to the crank and the other half can move a bit. It's held in place by a bearing of sorts, its rotation is resisted by relatively long springs (two usually, though I'm not sure on the m5 flywheel), these long springs allow quite a bit of rotation of one half compared to the other (lets say 25degrees for the sake of argument, I don't know what it actually is, dig for some technical info if its important!) and their strength would have been selected and 'tuned' for the car. To stop everything bouncing backwards and forwards, the two halves are damped by some means, I'm sure I've seen friction plates mentioned somewhere.

So, when a cylinder fires, it pulses the crank a bit (accelerating it for a very short time), then the crank coasts/slows down a bit until the next 'pulse' comes along and gives it another pulse. When the crank is pulsed, the springs compress and when the crank is coasting the springs expand; if done correctly all of this will allow the second flywheel half to move much more 'steadily' and smooth out much of the pulses.

In a slightly different way, all the dual mass flywheel does is absorb the single pulse and tries to distribute it more evenly between the pulses, smoothing the drive.

If anything in the flywheel is defective, it will affect how all of this works. A broken spring, worn friction plates and worn bearing all have their effects.

Now, after all of that, at 2k rpm I'm pretty sure the dual mass flywheel isn't meant to be doing much, well a fully functioning one at least. A defective one might well introduce problems and vibrations, I'm not sure what though.

The main problem is that to have it inspected means taking off the transmission, you might as well have it replaced if you're going back in there as well as the ream main seal (rms).

I'd change the engine and transmission mounts, check everything else thoroughly (myself or at least be present with the mechanic) and then if it persists, let it develop for a while, it may become blatantly obvious what is causing it without you having to spend a fortune.

If I've said anything incorrectly I'd welcome correction by anyone.
I hope somehow this helps.

Great post, ger. Lots of interesting stuff, especially about the dual mass flywheel. So that's why the clutch plate on the M5 doesn't need any springs.

A good DMF has about 3/4" relative movement between the two halves at the outside diameter. And I don't think there is any dampening as the two halves can be moved easily relative to each other with none of the resistance you would expect if it was dampened somehow. I can feel the 3/4" movement as a slight clunk when clutching/declutching crawling through the Timmy's drive-through (new DMF), but never during normal driving. I wonder if that is the "pop" the OP is hearing?

I have a subtle vibration/noise at 2500 rpm under a moderate load like normal acceleration up a hill, especially in second gear. It's not a high frequency vibration. I can feel it through the shifter. For various reasons I have changed the oil filter mounts, the engine, tranny, and exhaust mounts, the DMF, the clutch, the giubo, the centre bearing, all cam chain tensioners, and I have done the solenoid board mtce, with no change in the noise/vibration. I'm not saying it is not worth changing those components, just that it didn't work for me.

If I push the shifter forward gently while driving under load in 2nd or 4th or pull it backwards in 3rd (i.e. always towards the neutral position), I can feel the vibration much more strongly. The only reason for this I can think of is that the various shifter detents, which have settled into a nice unloaded neutral positions, are loaded up and make more direct contact with the engine/tranny assembly. So which one is generating the vibration, the engine or the tranny? And why only at 2500 rpm? I have to think nightkrawler may have it right. These cars have some kind of incurable resonance in the 2000-3000 range.

Based on many posts where some one has posted a question asking if this or that noise is normal, and the response has been, holy ****, don't drive that car, it's pretty obvious a lot of people are quite insensitive to mechanical noise and vibration, which makes me wonder how many owners have this vibration but don't even notice it. And I'm not knocking that. It beats being over-sensitive.

I agree with your suggested option of living with it until it gets bad enough the cause becomes obvious. Apart from planning more some VANOS solenoid checks, that's what I am doing.

 

[goodmaj]

A good DMF has about 3/4" relative movement between the two halves at the outside diameter. And I don't think there is any dampening as the two halves can be moved easily relative to each other with none of the resistance you would expect if it was dampened somehow. I can feel the 3/4" movement as a slight clunk when clutching/declutching crawling through the Timmy's drive-through (new DMF), but never during normal driving. I wonder if that is the "pop" the OP is hearing?

Wow, that's a lot of stuff replaced and you're still there...wow. On that "pop," I'd have to say it's most noticeable when leaving 1st gear around 3000 RPMs. If I come out of first and don't immediately go into second I'll get a pop almost every time. Definitely noticeable too at slow speeds, like when I'm going thru a drive thru....accelerate a bit, put clutch in, pop/brake. Will try for a video tomorrow.

 

[mattmor]

I have a subtle vibration/noise at 2500 rpm under a moderate load like normal acceleration up a hill, especially in second gear. It's not a high frequency vibration. I can feel it through the shifter. For various reasons I have changed the oil filter mounts, the engine, tranny, and exhaust mounts, the DMF, the clutch, the giubo, the centre bearing, all cam chain tensioners, and I have done the solenoid board mtce, with no change in the noise/vibration. I'm not saying it is not worth changing those components, just that it didn't work for me.

If I push the shifter forward gently while driving under load in 2nd or 4th or pull it backwards in 3rd (i.e. always towards the neutral position), I can feel the vibration much more strongly. The only reason for this I can think of is that the various shifter detents, which have settled into a nice unloaded neutral positions, are loaded up and make more direct contact with the engine/tranny assembly. So which one is generating the vibration, the engine or the tranny? And why only at 2500 rpm? I have to think nightkrawler may have it right. These cars have some kind of incurable resonance in the 2000-3000 range.

I recommend checking out this thread: BMW 1999 E36 M3 – How To Change Transmission “Detent Pin” Bushings - BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)

I think you/nightkrawler might have the answer unless nobody complained of this vibration when the car was brand new. After all, some newer luxury motor mounts are "active" in that they adjust stiffness in response to engine speed.

From this link (which is also very instructive on DMF BTW):
"Dual mass flywheels are tuned systems and must be matched to the engine torque curve, engine resonant characteristics, vehicle load curves (including axle ratio/tyre size calculations)."

Based on many posts where some one has posted a question asking if this or that noise is normal, and the response has been, holy ****, don't drive that car, it's pretty obvious a lot of people are quite insensitive to mechanical noise and vibration, which makes me wonder how many owners have this vibration but don't even notice it. And I'm not knocking that. It beats being over-sensitive.

Sensitivity definitely makes it difficult to read into the symptoms being presented. Another aspect is that many things could be contributing to an owner's vibrations and sounds which makes it a lot harder to define which is which. The only apparent cure (after visual inspection) being to replace all the usual wear and tear items that cause problems and see what happens.

 

[68FB]

Wow, that's a lot of stuff replaced and you're still there...wow. On that "pop," I'd have to say it's most noticeable when leaving 1st gear around 3000 RPMs. If I come out of first and don't immediately go into second I'll get a pop almost every time. Definitely noticeable too at slow speeds, like when I'm going thru a drive thru....accelerate a bit, put clutch in, pop/brake. Will try for a video tomorrow.

I didn't specifically change all that stuff to fix the vibration, it was for other reasons like a slipping clutch, VANOS noise, jerkiness on pull-away, etc. But is has surprised me that none of that work make any difference to the vibration.

 

[68FB]

I recommend checking out this thread: BMW 1999 E36 M3 – How To Change Transmission “Detent Pin” Bushings - BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)

Another interesting thread, mattmor. Thanks. The M5 tranny has the same detent pin for the shifter rod but mine's not jammed and allowing the shifter rod to float. I don't have any fore-and-aft slop and no visible movement while driving.

 

[mattmor]

Another interesting thread, mattmor. Thanks. The M5 tranny has the same detent pin for the shifter rod but mine's not jammed and allowing the shifter rod to float. I don't have any fore-and-aft slop and no visible movement while driving.

Gotcha. Do you think it could be bushings, springs, or drop pins?

 

[mattmor]

68FB,

Did you mean that you actually moved the shifter toward neutral or just put pressure on the knob in that direction? I tried just putting slight/moderate pressure and noticed a tiny increase in vibration, but it felt more like I was just in tune with the vibration rather than an actual increase.

 

[68FB]

mattmor,
I just put gentle pressure on the knob when it's in gear and push it towards the neutral direction until I feel some resistance. And when I say I feel an increase in vibration, I mean just in the shift knob. It doesn't change overall. Pushing on the knob is putting the shift lever in more direct contact with whatever is causing the noise and vibration. It could something internal to the gear box or it could be an engine vibration coming through the gearbox.

The increase in vibration under my hand when I put pressure on is dramatic and perfectly in time with the noise I can hear. So you feel very little increase when you do that?

 

[mattmor]

mattmor,
I just put gentle pressure on the knob when it's in gear and push it towards the neutral direction until I feel some resistance. And when I say I feel an increase in vibration, I mean just in the shift knob. It doesn't change overall. Pushing on the knob is putting the shift lever in more direct contact with whatever is causing the noise and vibration. It could something internal to the gear box or it could be an engine vibration coming through the gearbox.

The increase in vibration under my hand when I put pressure on is dramatic and perfectly in time with the noise I can hear. So you feel very little increase when you do that?

I'm getting a better picture now. Thanks. I'm hypersensitive to vibration these days, so I can certainly imagine how someone would feel my shifter and think there was no vibration at all.

I am getting vibration around 2,500rpm sometimes, but it feel more like from the body. I need to replace the bushings for the oil filter/power steering mounts and then make sure that banjo is free from the body because I can see it touching the wheel well now. I'll be using your tip about a ball-peen hammer if the new bushings don't make up the difference for sure. Too much on my plate for that right now though. I still have new lower control arms and sway-bar links sitting in my trunk ready to be installed