Low speed scrape

[E3Owner]

Hello,

Taking another stab at this cause no one seems able to figure out what it is. I posted this issue before and I am still having the issue which has got worse.

My 325i convertible has a cyclical scrapping noise/ feel from 0 to 20 and 20 to 0 mph.

Most recent work to try to address the issue include

1- New CSB
2- New trans output shaft and diff input shaft seals
3- New diff mount
4- New transmission mount

Other
New diff passenger side output axle shaft seal due to leak.

I’ll appreciate any expert knowledge you can share to help me figure out what’s causing this. Please.

Thank you very very much.

[jgilber0]

Is your shift linkage rubbing against the driveshaft? I’ve seen many posts about that.

[E3Owner]

Thanks. No the links were refreshed when output shaft seal was replaced. Shifts great!

Also the scrapping is a solid froom froom froom. I believe it feels as if the rear is bouncing up and down very slightly but that could be my imagination. Becomes more noticeable at about 15 mph and is gone at about 25mph.

[E3Owner]

I was trying to edit previous post but the site seems to be having issues. I wanted to add

Also the scrapping is a solid froom froom froom. I believe it feels as if the rear is bouncing up and down very slightly but that could be my imagination. Becomes more noticeable at about 15 mph and is gone at about 25mph.

[twright]

Can you tell which direction its coming from? Can you hear it with the windows open or closed?

[ADEN]

My rear subframe bushings used to do this to me. Gets more noisy if i have passengers in the rear seat or heavy load in the trunk all this happens in 0 to 10 km speeds.

[E3Owner]

Sorry work is a bear.

It seems to be coming from the right rear. It can be heard with windows open or closed.

It is cyclical/rotational like a warped rotor or out of round drum except it happens over a limited low speed range. If the disk/drum were at fault I would think it would happen at all speeds, more so at higher speeds.

The brakes checked out fine, also they work great, no pulsing, vibrations at any speed. The tires are brand new.

Subframe was checked out when the diff support bushing was replaced.

Could worn diff gears cause this?
Could driveshaft cause this?
Could bad half shafts cv joints cause this?

Anything else?

Thank you for your input.

[325e '87]

Rear wheel bearing? When mine went it sounded like I was running over squeak toys.

[E3Owner]

Considered that but one rear wheel bearing was replaced a while back plus the feel/sound is the same going straight or turning left or right.

The driveshaft csb was replaced last year and the mechanic said it’s there is no play in the join but would a dried up join feel/sound this way?

[E3Owner]

Hi all. Got a couple of suggestions concerning aftermarket wheels and lugs being too long. The car has oe Alpina wheels so no centering ring required. The idea of lugs being too long and rubbing on the hub is plausible and will investigate though I would think it would be happening all the time and more so as the parts heat up on long (5hr) trips.

I would like to hear from anyone who has had driveshaft problems and how did it sound/feel like?

Thank you again.

[Sea Aych]

I was plagued by driveshaft problems for a long time. Worn u-joints will make the car vibrate, shake and/or drone at a certain speed, depending on how worn out everything is. You'll be able to feel it, if not through your seat by putting your hand on the transmission tunnel while you're moving.
If a CSB is totally hosed, it'll clunk aggressively when you pull away from a stop, but if it's just starting to go it can also shake like an out of balance driveshaft or worn out u-joints.

Stupid question, but have you popped off your brake rotor to see if the e-brake mechanism is rusted or stuck, or broken and rubbing against the inside of the rotor? That caused some squeaky scraping for me once as well.
Good luck!

[E3Owner]

The CSB and guibo were replaced last year along with the tranny output shaft seal and diff support bush. Problem was there before and got worse after, not to mention that the shop managed to break the diff cover.

I took the car to another shop for diagnosis and they said the brakes are fine but they also said the cause maybe that the car is sitting about .5 inch lower on the rear left corner which seems bogus to me. What do you think?

This weekend I am going to pull the rear wheels and take the rear brakes apart.

[cory58]

When I bought my Touring it had the same sound. One of the rear brake backing plates had rusted out and was no longer holding the e-brake springs. I'm sure the noise did not go away at higher speeds but I could not hear it due to ambient noise.

[E3Owner]

Hello,

Yesterday I took the rear brakes apart. No broken springs or seized components. The e-brake engages and releases fully no binding or any such thing and the shoes expand and contracts just fine. The only thing I did noticed is that the brake drum had some build up on about 1/4 to 1/2 of the shoe matting surface the rest was shinny, weird right?

Been reading on diff and transmission issues. Supposedly high spots on diff gears can cause something similar but at all speeds so not quite the same thing I am experiencing.

My tranny gets very clanky when clutched at a light but shifts like butter and very precise. I could not find any info on that or how it may relate to slow speed rub/noise I hear when the car hits that narrow speed range 15-25 mph.

Happy 4th every one!!!