Once and for all, driveshaft/differential clank?

[clawhamm3r]

No idea on the CV length but if your guibo was previously replaced can you rule out the driveshaft wasn't replaced with the incorrect one and maybe the cause of the noise?

Did you bang out the studs and see if it fit? I went back through my archives to see if I had a pic of my d/s from when I did the job to compare the CV size to but didn't have any.

Did you pop the cover off your old CV and make sure it's good and packed full of grease?

[mrgizmo04]

Is the overall length of both driveshafts the same? Is there some other section of the driveshaft on the right that is shorter? To me it looks like you essentially have a longer driveshaft due to the length the cv joint adds.

Sounds like incorrect part. It comes with studs? Its prob for a car that attaches to the diff input flange via nuts. That is not how it attaches on our cars. On our cars the diff input flange is threaded so studs on cv joint can not work. Even if you are able to press them out and the bolt pattern and hole size will match up to input flange, I'd go back to paragraph above about overall length.

You can see what a new proper cv joint looks like here from several angles: https://www.ecstuning.com/b-genuine-...YaAp4fEALw_wcB

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[OEMaddict]

Driveshaft had a little amount of grease left but it look like it definitely was running dry, little on the CV joint and less on the diff. As for the overall length, the rest of the DS seemed to be mostly identical to the old one, it looked like it was a core with a bad CV joint and so they replaced it with some aftermarket one. At this point, is it not worth putting it in my car and instead calling the driveshaft company back for a refund?

[mrgizmo04]

If the rest of the new driveshaft is identical in length to your old one, and the only difference is that the new one has a bigger/longer cv joint it will physically not fit.

Are the distances I marked in red the same? Seems like new one is about 1/4inch longer.

So if all the other lengths of the driveshaft are the same and the new one adds 1/4inch (or whatever the actual length is), I would not try to stuff it into the car, unless the spline in the middle of the driveshaft has some more room to move (which I dont remember it having much wiggle room) to take up the extra length of the cv.

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[OEMaddict]

If the rest of the new driveshaft is identical in length to your old one, and the only difference is that the new one has a bigger/longer cv joint it will physically not fit.

Are the distances I marked in red the same? Seems like new one is about 1/4inch longer.

So if all the other lengths of the driveshaft are the same and the new one adds 1/4inch (or whatever the actual length is), I would not try to stuff it into the car, unless the spline in the middle of the driveshaft has some more room to move (which I dont remember it having much wiggle room) to take up the extra length of the cv.

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I measured and it was exactly about 0.25" longer than the outgoing one. I spoke with the company again and after going back and forth he remained stern that "it will fit and you will be happy". So I figured I would just try, and end up chargebacking the thing with my CC if it goes south if they still refuse to return the damn thing...

Good news though, is that I asked on the M3cutters forum and they had a video showing the exact problem: and they confirmed it was the rear CV joint making the issue. Hopefully this will take care of it.

[maupineda]

I am not familiar with the design, but unless you have 0.25in to spare on the other side (maybe the spline side can absorb this) you will have a problem fitting it.

[mrgizmo04]

While it might fit if you stuff it in there, I think you will put additional compressive load into the drivetrain and all the associated bearings and joints which could lead to other premature failure.

Personally I don't feel very positively about it.

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[bigjae46]

That will physically fit but you will likely introduce a vibration into the car. The CV joint will bind up since the extra length will prevent the CV from moving freely.

You just need to tap those studs out. They use those studs to mount the driveshaft to the balancer.

If there is a persistent vibration and the flex disc, front bushing, and center bearing are in good shape then I would suspect the diff. The CV likely won't go bad unless the boot is compromised. BTW...this is coming from someone who sells driveshaft rebuilds.

The theory is the diff is the common culprit. The M Lock has a long and short axle stub. The internal assembly in the LSD develops play as the clutch discs and steels wear.

[OEMaddict]

Thanks for the info bigjae. I also agree with everyone that putting the remanufactured driveshaft in the car might cause issues but I'm caught between a rock and a hard place; after days of arguing with the owner of the company he says quote

"This is the exact correct driveshaft for your car.
The bolts will work perfectly and the cv heads are pretty much identical.
Bolt the driveshaft in and drive the car I promise you will be happy."

I don't even know where to begin to get a refund and ship it back to them. I figure I could start a chargeback but I'll wait for that until the last second if they're being very unreasonable.

As for vibrations, I don't have any yet (knock on wood), but this guy has the same "clank" noise and replaced his rear CV joint.

[bigjae46]

Thanks for the info bigjae. I also agree with everyone that putting the remanufactured driveshaft in the car might cause issues but I'm caught between a rock and a hard place; after days of arguing with the owner of the company he says quote

"This is the exact correct driveshaft for your car.
The bolts will work perfectly and the cv heads are pretty much identical.
Bolt the driveshaft in and drive the car I promise you will be happy."

I don't even know where to begin to get a refund and ship it back to them. I figure I could start a chargeback but I'll wait for that until the last second if they're being very unreasonable.

As for vibrations, I don't have any yet (knock on wood), but this guy has the same "clank" noise and replaced his rear CV joint.

I think nothing wrong with a rebuild driveshaft but a sometimes it is not necessary. There's nothing to really clunk in the driveshaft unless something is really loose or obviously failed (center bearing). If anything you'll get a vibration with a driveshaft issue. Probably the diff.

[OEMaddict]

I think nothing wrong with a rebuild driveshaft but a sometimes it is not necessary. There's nothing to really clunk in the driveshaft unless something is really loose or obviously failed (center bearing). If anything you'll get a vibration with a driveshaft issue. Probably the diff.

Oh I was referring to my particular rebuilt driveshaft due to the discrepancies with the rear CV joint I have and how that might have issues, in pictures above. The price was hard to beat ($460 including new CSB, u-joint, rear CV joint) so I thought it would be a good deal compared to $280 for the CV joint alone.

I had a feeling that the CV joint was the failure point, posted the noise I was getting on m3cutters and two people both told me they replaced their CV joint to get rid of noise, which was a sigh of relief... now I need to find time to put the rebuilt shaft in to see if the CV joint from the new driveshaft is even compatible; I'm hoping to not have to pull it off again to put in the old one + new CV joint.

I see what you mean though. It looks like I will have to inspect the CV boot more closely... I noticed there wasn't much grease left in the joint.

[bigjae46]

I would try and see if the center of the CV can be pushed into the top cap.


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[TexaZ3]

Thanks for the info bigjae. I also agree with everyone that putting the remanufactured driveshaft in the car might cause issues but I'm caught between a rock and a hard place; after days of arguing with the owner of the company he says quote

"This is the exact correct driveshaft for your car.
The bolts will work perfectly and the cv heads are pretty much identical.
Bolt the driveshaft in and drive the car I promise you will be happy."

I don't even know where to begin to get a refund and ship it back to them. I figure I could start a chargeback but I'll wait for that until the last second if they're being very unreasonable.

As for vibrations, I don't have any yet (knock on wood), but this guy has the same "clank" noise and replaced his rear CV joint.

If you really want to return it, just tell them you tried putting it in, and it didn't fit.

[Irhase46m3]

That list is incomplete. There is a lot of slack in the driveline that you need to isolate, all the way from the tranny to the output shafts. Loose/worn clutches in the diff or improperly shimmed diff will also add to the clink/clunk.

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This!

To me it sounds like your diff has too much play, this clicking noise is more pronounced on the SMG than the manual as the SMG clutch slave doesn't operate as smooth as the manual - If you haven't already changed your diff fluid, i suggest you change it with the OEM bmw fluid (the SAF-XJ+FM Booster) and see if it helps