I'm chasing a vibration on my 2004 JCW, 100% stock, that has perplexed me so far.

Going down interstate, if I accelerate moderately or heavily in 6th gear and I'm above ~3000rpms the car shakes pretty hard until I let off. Below 3000rpm, it accelerates slowly of course, but no vibration. If I'm in 5th gear above 3000rpm, no vibrations at all.

I've changed wheels so I know its not a bent wheel or tire balance problem. It it was a high load, low rpm thing I would expect it to vibrate at lower rpms in 6th gear.

Any ideas, this has me nuts trying to figure it out. Could it be DME related, at high load in 6th gear, something isn't happy engine wise?

Thanks!

 

Had nearly the same exact symptoms.
Believe it or not - I had inexpensive engine mounts that only lasted a few thousand miles. When I changed them out trying to solve another issue - the shaking under acceleration and hwy speeds were no more. Unfortunately it didn't solve the issue I was chasing.
Other things to look for with respect to shaking:
Lower Control Arm bushings
Inner ball joints
Worn drive axles
but I might also suspect worn tie rods (even though the car seems to drive straight)

 

Hmm, maybe it could be either of the engine or trans mount, . The drive axles have been replaced as well as the control arm bushings. Not sure on the ball joints or tie rods so I'll take a look at them for any sloppiness

Thanks for the thoughts!

 

You may also want to consider transmission bearings where axles enter tranny. I had similar problem but at lower speed; 30 mph around 3000 rpm.

 

That is a something to consider as well. I wonder if it only happening in 6th gear helps pinpoint what could have failed in the trans.

Thank you, I'll add that to my inspection list for the weekend. Not sure how much I can see without pulling the trans, but we'll see.

 

If you have gearbox bearing issues that bad the grinding noise will be very audible. Also the axels are not inserted into bearings but into the diff which has two bearings on the outside to hold it in place in the housing. Except for the axel carrier bearing which is not in the gearbox.

The 6speed gearbox has three shafts carrying gears, if one shafts bearing is toast you should also notice it in another gear. But again, if its a bearing your will hear a hard grinding noise.

I highly doubt the gearbox is your issue.

Start would start with simple things, get your rims checked for straightness and balanced. I had a Z3 once which would cause a vibration between 100-110kph. Turned one rim was bend.
Turned out you already excluded this.

I would look at live obd2 data, it might be something like fuel pressure because its only at high speeds. Is your steering wheel shaking or the entire car?

 

It's possible this is mechanical, checking fuel pressure is a great idea. You feel the shake through the entire car, not just the steering wheel. Thanks

 

If its the entire car then its most likely engine related and not suspension or steering.

I would start logging live data to see if certain values go wonk when it happens.

 

Update on this, not seeing anything suspension or hub related. So I moved to checking engine vitals, but it seems I'm getting no communication to the DME via the OBD plug.

I may have the seemingly common "broken communication wire" so time to pull out the continuity meter and start checking. Thanks

 

If suspension and related steering check out and in reasonably good working order - I would reiterate by suggesting motor mounts = upper and lower.
I was surprised by replacing my lower engine/torque mount in addition to adding the powerflex inserts (#7 & #6 ).
I also replaced my upper engine mount. However, for the upper engine mount; I upgraded to the more expensive Vibra Technics style mount (the link to the Vibra Technics mount is for my early pre-facelift '04 R53. Yours maybe different if you have the facelift 04 JCW.) Regardless - my motor mounts were prematurely worn and we're the culprit causing my vibration issues.
I hate to have you throw unnecessary money/parts at your Mini. Just something to consider from my personal experience.
Hope you figure it out.

 

The axles enter the transaxle (combination of transmission and differential in R5x MINIs) through bearing on the side of transaxle. That’s what I meant.

The entry points are sealed by metal plate covers, which have a tendency to come off, left out in a previous repair, or damaged. When this happens, dirt, sand, stuff get to the bearings, accelerating bearing bearing wear, and hence, vibrations. Because replacing them is a *****, most people/shops avoid them.

 

I know because I have taking a Getrag gearbox apart to replace all bearings.

My point was that if your bearings are that bad that the axels shake, you will definitely hear an almost unbearable grinding noise. Look at the linked thread, I drove it home for 250km with this damage and the noise was bad, like really bad, at 100kph.

 

Oh - One last note;
Although I highly doubt it is your issue but I now recall posting about a similar vibration issue (about 2wo years ago), upon acceleration. It usually occured around 2,5 - 3k rpm. One day while I was under the car, by chance, I discovered that the 3 bolts that holds the mid axle bearing/carrier on the passenger side had come loose (but not fallen out). This caused the carrier bearing to move up and down. I tightend the bolts down and that solved my issue in that scenario.
That was a weird one for me. I had never messed with that carrier bearing ever before. It remains a complete anomaly to me to this day.
It might be something to look at when your underneath the car?

 

It's been a few months now and the OP has yet to post whether or not they discovered or resolved the problem cause for the described vibration under throttle.
Ironically - I have just suddenly experienced the same or similar violent shaking upon acceleration of my 04 R53.
This was like none other I've experienced in the past due to worn motor mounts.
I found it hard to believe but this time it was due to a failed driver side CV AXLE. Upon driving and turning, I never once heard any clicking or clunking indicative of a bad CV joint. I had the car up on jack stands several times evaluating the condition of everything underneath the front end. Especially focusing on the CV axles by pushing, pulling, turning, and pushing up and down whilst feeling or listening for any unusual play or noise. Nothing. All seemed fine. No noise.The intensity of the vibration eluded me for days until I finally pulled the driver side axle and discovered that the needle bearings on one of the knuckles/bearings had exploded out; leaving the CV joint with only 2wo of the remaining bearings to support it's function.
My violent vibration issues under acceleration was completely resolved by replacing the CV axle.
Point is - "Don't believe everything you don't hear"

A lengthy anecdote, I admit but I hope it helps someone else

 

Hello, thanks for the update on your issue.

I've been traveling for work a lot lately, and I haven't been able to further diagnose. The mounts were replaced, but I'm still looking. I guess I need to pull those axles and take a look even though they were replaced 20k ago based on the maintenance records I received when buying.

Interesting, did you only feel the vibration in the higher gears at heavy acceleration ike myself or all the time?

 

Yes. Initially the vibration occurred upon accelerating from around 55-70mph in 4th - 6th gear. The symptoms came on suddenly while merging on to the interstate. But only upon accelerating between 3,000 - 4,200 rpms +. The more throttle/rpms + speed the more violent the shaking/vibration. Within a little over a week time the vibration got worse = accelerating normally from a dead stop to increased vibration at lower rpms and lower speed.
As mentioned - I never heard any noise or the tell tale signs of a bad CV joint. The car up on jack stands and hands on; nothing seemed out of the norm.
It was only until yesterday while driving through town that I felt the vibration at lower 35mph speed and started hearing a very faint intermittent random squeaking sound upon mild acceleration within the in town speed limits.
Here is a link to my recent post in the Hatch Talk forum: Violent vibration at hwy speed - upper strut mounts or other causes??

 

Thank you for the extra detail, I haven't driven mine much since I swapped mounts, but I know that wasn't the problem now. It sounds similar to mine, just yours progressed faster it seems. I'll add pulling axles as next on my list when I get back home. Thanks!!

 

As you can see in the above image I posted; I probably would have never known the Inner CV was damaged until I separated the carrier from the inner CV bearing boot.
There was a sufficient amount of grease. I probed the inner carrier pulling out a few remnants of the failed bearing.