Once and for all, driveshaft/differential clank?

[OEMaddict]

A few years ago, I posted this on the M3Forum, but never got a solid consensus on what this noise is, been 5+ years since I first got this issue and now checking to see if anyone else has this problem.

The noise, which sounds somewhat like a metallic "clink", not a clunk, occurs whenever I put my foot on acceleration, as well as when I let go. Easily reproducible and it's pretty noticeable/loud. It doesn't affect performance whatsoever and I have been living with it since early 2015...

I'm about to do rod bearings soon, as well as possible 6MT conversion, so I wanna know what the problem is before I pick up a remanufactured driveshaft, or if it's a differential issue. I'm leaning on the driveshaft issue side, possibly CV joint or U-joint, as Driveshaft Specialist in Texas has remanufactured ones with new U-joint, CV joint, CSB, etc. I will probably go that route. If anyone has had this issue before, please let me know!

[Cubieman]

I have an intermittent clunk issue, I have a slight tear in my flex disc and the rear diff bushings don't look great either. I would do a visual check on these items to see if it's something cheaper like diff bushings.

[clawhamm3r]

Driveshaft CV?

[OEMaddict]

Thanks guys, I think either one of those issues could be the problem. I'm gonna start looking at the driveshaft and then focus on the diff if it's not fixed as I'm not convinced anymore of which it could be... I found very few videos where other M3 guys have had this issue but seems none of them know what it is either.

[jcreme]

Could be anything worn out in the driveline. However, my first look would be forward of the diff because the noise sounds very sharp and not sound muffled at all. I worn diff sounds like that, but a worn diff will sound like the noise is transmitted more though the body of the car. This noise sounds like we are hearing it directly. Take out the drive shaft and check the guido, the splines, and the CV for obvious wear.

[///Mac]

Agree that this noise is most likely ahead of the diff. Try to simulate the noise while under the car to see if you can reproduce and isolate it. Car off, parking brake engaged just enough to put a load on the driveshaft while still allowing it to turn, start to rotate the driveshaft back and forth using a quick initial motion. That could reproduce the noise. Maybe?

[R60BBA]

It is either:

• Giubo
• Centre universal joint
• Rear CV joint (before the diff).

You can try and tackle each one individually or replace with a new propshaft (which may be more cost effective).

[COVID-19]

^^+1
I saw a video where the guy puts a small amount of grease (almost nothing, on the male) where the driveshaft splits in half.

[mrgizmo04]

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.

Sent from my SM-G950U using Tapatalk

[Shadytype]

When is the last time you checked your pads? Almost sounds like a pad is dragging a bit and the clink could be due to a worn out shim or missing clips.

Had a friend with an mdx had a near identical sound. Had the truck at the dealer 5 or 6 times. Couldnt reproduce, swap out awd system etc...
He asled me to look at it. I had it for about a week. Driving it daily. Racked my brain. Then i thought ot was a loose lug on a wheel... took em off to peek at the LCA and bushings. Realized no spring clips/shims... it was his pads banging back and forth. Bought new pades, put the clips in. Problem solved.

[OEMaddict]

Brake pads? I had them replaced about 800 or so miles ago with OEM stuff, didn't change the noise after replacing. I do believe I have a weird noise coming from the right front pad though, but that was after I changed it, and only when I'm turning left for some reason. Hasn't been the clank noise that's been bothering me for 5 years now though.

[OEMaddict]

I received the remanufactured driveshaft, all stuff looks good but the CV joint is about 1/2-1" larger than the previous CV joint off my car. My old driveshaft honestly looks in pretty good shape, and the old giubo even looked like it was replaced at one point it was so new. So it's hard to tell if the clanking noise is coming from the driveshaft... I hope it's not the diff.

However, there were mounting studs on the new CV joint they sent me versus the Torx head bolts, I tried prying it out with pliers but no dice. I called the driveshaft company and they told me just to tap the old ones out with a mallet... otherwise the driveshaft looks pretty identical other than the larger CV joint, should this be compatible onto the diff?

[Ceelooboob]

The new driveshaft cv joint should be the same length as the old one. I recently replaced my driveshaft cv joint and the new one was identical to the old one. I’ve seen other bmw models that come with studs in the cv joint but not the e46 m3. Are you sure you have the right driveshaft? If the driveshaft is really an inch longer it might not even fit in there in between the diff and trans.

[OEMaddict]

The new driveshaft cv joint should be the same length as the old one. I recently replaced my driveshaft cv joint and the new one was identical to the old one. I’ve seen other bmw models that come with studs in the cv joint but not the e46 m3. Are you sure you have the right driveshaft? If the driveshaft is really an inch longer it might not even fit in there in between the diff and trans.

Yeah that's the part that worries me... you can see in the pics that the joint is a bit longer than the one on the left. I'll find out soon when I put it on the car, hoping it'll go right in.

[OEMaddict]

Bump - does anyone know if this CV joint would be compatible with our cars? Also FYI, I replaced the giubo on my car, the old one did not look worn at all, and unsurprisingly this did not fix the issue. I tried playing around with the old driveshaft to replicate a noise but nothing.