Noise 1980 240D help ID
 

I have a new noise that only happens when I am moving and starts at about 10mph in any gear.

I have searched the forum for descriptions of Noises others have heard or hear.
This is not a grind, whistle or growl or thump or squeal.

It sounds like what you hear when you blow over the top of a large bottle and it's loud and gets louder the faster you go, until it peaks at about 30mph.
Does it with clutch engaged or disengaged.
Depressing brakes does not alter the noise, turning the steering wheel changes nothing.

It sounds like the noise is coming from under the gearshift of the manual transmission.
But I'm starting to think it may be coming more to the passenger side front wheel or somewhere in between.

I am kinda scared to keep driving the car to try to pinpoint the noise in fear I will tear something up.
My wrenching bud seems to think that somehow we have reverse and forward gears partially engaged at the same time.
But it seems to me this would be close to impossible because the gears are tight, either engaged or not ie there is no slop there.

Hope the noise description helps.
If it will help I will record the noise and post it.
You will have no problem hearing what I have tried to describe.

Appreciate the help in advance.

Well if you think it is drive train related - have you checked oil / fluid levels?

Sounds like a bearing is going out, possibly Throwout or Carrier?

... I'd think it's the air filter being off... or a leak in the intake somewhere.
but it could easily be a bad throwout bearing, or input shaft bearing.

My vote is for the center support bearing. I was working on a VW Toureag, and it had a similar noise. I put it on a lift with someone driving it with me underneath. I was able to pinpoint the noise and found it to be the center support bearing......Rich

Is the speedo jumping around when this is happening?

All checked and good.

No

Just jacked car up and and ran through the gears and got the noise, waiting for additional person so I can get under car to find the source of the sound. Is there a test to determine if this is the Throwout or Carrier bearing once I am under car? I will check the Center Support. Check back soon.

If when depressing the clutch pedal ( engine running) the sound changes volume or tone it is most likely the throw out bearing.

The best listening device is a mechanic's stethoscope or if you don't have one a wooden stick works pretty well also. Just place one end of the stick on the bell housing or the carrier bearing and the other end up against your ear. You will be able to hear the growling noise.

Great, that test rules out the TOB. Sound does not change when engaging or disengagement of clutch.:)

Sound varies only with speed only.

No stethoscope but I do have allot of wooden sticks. I was kinda scared to crawl up under the car while going through the gears. This will surely be the way I will investigate noises from here on out.
Thanks:)

PLEASE make sure the car is securely positioned on jack stands before getting underneath the car - running or not.

You will probably need to crawl under the car but PLEASE make sure the car is securely positioned on jack stands before getting underneath the car - running or not.

I'm having exactly the same sound and problem - it just cropped up this weekend on a long drive. Sounds like an owl is trapped behind the dash or in a wheel well, and I can feel the slight vibration in the accelerator pedal. It happens when I hit 45mph, and was intermittent at first and now happens every time I hit 45.

I have it at the shop down the street to see if they can diagnose it. My money is on a wheel bearing. It sounds like from this forum the same sound could happen with the speedometer cable, but my speedo isn't acting weird.

I'll post what they come back with.

Well my mechanic thinks the problem is the driveshaft bearing. The bearing support is obviously total rubbish and the bearing is making noise as well. It's hard to tell if it's the same noise but we'll replace it and report back.

He took the wheel bearings out and said they seemed fine...

Good luck Treeman.

Took the car to a trusted Mechanic, We went on a test drive, we had maybe got out of his driveway. and he say's RearEnd, after another 10th of a mile he say's strong chance it will be passenger side rear wheel bearing, but still could be the Diff. We will soon find out as I am taking it to one more guy to get his diagnosis. Thought I would share what I found so far. Will let yall know what the second opinion is. I want to Thank everyone for input. I appreciate you guy's and the entire forum Happy New Year!!!:)

Does the tone change in pitch with a change in speed? If so then it could be a wheel bearing or a bearing in the diff.

If it does not change in tone, check your brake lines for flexibility, bleed your brakes (flush them, not just a single bleed) and then test the car.

I had a howl in the rear of my 1978 300D that didn't change pitch and it turned out to be a stuck caliper. Bleeding the brakes got me by for months but the caliper was just diagnosed as really stuck by my friend, who bought the car from me.

If you hear only one single tone then it's most likely the brake pad heating up the piston, heating up a small amount of water which expands and vibrates the pad against the rotor at a constant frequency.

If the tone changes, then look at the wheel bearings and the differential. You can save a lot of money if you do the work yourself. A LOT.

Before you get into all the expensive stuff, try fixing the easy stuff first.

Phil Forrest

I made a Video Here is the Noise I described
 

I took it to a Transmission shop. The Owner told me it is nor a wheel bearing, throwout bearing, locked brakes. He agrees with RollGuy it is the Center Support or Drive Shaft Support Bearing. I pulling the one off my parts car ant try to slap it in.

Here is a video I made to get the noise for yall. I know I sound like a Hillbilly, I am a Hillbilly. Thanks for all the help. The 1980 240D Howler - YouTube

I know a hillbilly when I hear one, and I also know a center support bearing noise when I hear one. My vote is yes on both :D

Glad you found the issue.

Inspect the flex discs while under there.