I hear a very loud noise coming potentially from the transmission at higher speeds on the highway (80mph). The noise doesn't come from the engine, I am almost certain. I know talking about noise is very difficult. Does anyone know?

Isn't there a center bearing that could be making the noise? I've never heard of a transmission making a noise like that.

If you have access to a lift, I'd put it up in the air with someone in the car.

Thanks,

David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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could be a whole bunch of things, I'd crawl under and wiggle the speedometer cable, output flange, rubber center mount, you wouldn't be able to get at the center bearing without dropping the exhaust and shield. sometimes I get funny noises from my slushbox too, but only at low speeds, my noises are kinda like metal scraping lightly,

"guess I know where that screwdriver went, when I replaced the tranny.."

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R107.043 Euro 350SL (parts)(crushed)
W116.024 280se (crushed)
W114 280 (m110)
W108.067 280se 4.5
W108.068 280seL 4.5 (crushed)
W111 220SEB coupe
W110 200D went to the crusher
W110 190D sold sold sold

1970 Rover P6B

Used to own(1950 buick,1969 lincoln MK3,4G63t colt,87 300ZX, 79 F100, 92 XJ40)

i know that the transmission should make no noise as it is binding at high speeds... so it is something else.. you are right there must be a center bearing at the drive shaft, at least the W126 has one.

Another thing came to my mind: I have filled my fan clutch with silicone oil and it could be that the fan makes this noise??
This means the clutch is binding! grrrr. need to drain the silicone again.

I think you raise a good point. I'll bet it is your fan clutch (and thus why your clutch thread resurfaced!). I've only occasionally heard transmission noise when coasting to a stop, and it doesn't really sound like a bad one. Right now I'm chasing a rear-end noise in my car [roll eyes here].

Best Regards,

David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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I took the fan clutch out again (can make it in 5 minutes now, have done it 10 times now) and drained a lot of silicone (be careful not to overfill the clutch if you put silicone in). Now testing the fan on the bench:
after some resistance in the beginning I can freely spin the fan without much noticeable resistance.
I installed the clutch and now (with thick gloves) I can stop the fan at idle and it stops while engine is idling.
I can hold the fan with one finger to be honest. Is that what it should work ?

It sounds like you emptied too much fluid. If you can stop the fan like that then the clutch is bad. A test I would try it to pop the hood with the engine running. Then, sitting in the car and looking at the large crack between the hood and the dash, look to see if the fan keeps spinning after you shut off the engine. It shouldn't spin more than two rotations or so after the engine is shut off.

-David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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I just got a new fan clutch, enough experiments. Only problem with the new clutch: It is URO! I hate this company- they should be banned. I'll see if it makes a difference in noise and performance.

Then I got a real noise from the transmission. I can clearly hear it at idle and during driving, Sound is depending on engine speed. Someone experienced would for sure know what it is. Could be the primary pump as the noise is linear the engine speed. Not sure how to describe this noise. It could be a howling noise, clearly mechanical.
Does anyone know how a loud primary pump sounds?

First thought would be a torque converter whine. Have you checked your fluid recently?
Can you describe the noise?

Is it a whine?
Is it a knock?
Do you hear it in Neutral or just in drive?
You may want to use a long screw driver to hone in on the noise. Put one side on to your ear and the other side to part that you think is making the noise in the same way that you'd use a stethoscope.
Also check the power steering pump, alternator and A/C compressor.


Maybe with a little more info, we can help.

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With best regards

Al

Martin,
Is there any chance the noise is coming from around the bell housing? If so, one possibility (based on experience ) is that the starter may not be fully retracting.

If you think this could be the problem, you could try starting car. Then give starter a few good taps with a hammer or something like that in attempt to get the pinion to retract. Then go for ride and see if noise is still there.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Thanks Graham
Wow! starter gear not retracting...is this possible without damaging starter and starter gear?
I will crawl down this evening and really listen and a hammer to tap the starter.

Thanks Al,
it is clearly NOT PS pump and not alternator or A/C compressor.

Sound - whine or knock? ......clearly WHINE.

I hear it in all positions P/R/N/4
I'll crawl down with the crew driver to idetify more of the location and sound quality.
Best, Martin

To Graham's point, the starter may not retract completely, but that would be more a metallic sound then a whine.

Another question for you. Does the noise go away when the engine warms up?

What kind of shape is your fluid in and how old is your filter? It may be time for a fluid and filter change. I'm not familiar with the fluid couple transmissions on the earlier W109's. The later 722.0 transmissions have a drain plug on the torque converter, which is where most of the transmission fluid lives.

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With best regards

Al

Noise doesn't go away with engine warm. Noise stays the same.
The noise is clearly not metallic (no metal grinding or touching) but more like a whine of a gear.
Fluid: I changed fluid several times now but not the torque converter. I think the plug is frozen into place. Can't get it out... might this be the reason for the sound?

On my car, it was not a metallic sound (whatever that is). It sounded like a bearing that was not getting lubrication and about to seize.

I was fortunate that the pinion was almost retracting and was just making contact with the ring gear. The ring gear was fortunately not damaged.

I eliminated every other possibility before finding the real problem. As a result, I have new alternator bearings, new belts, transmission service, etc etc.

Martin - One other simple thing to check - Make sure that the heat shields above the exhaust pipes are properly screwed in place and not in contact with pipes or body except where mounted. I had this problem in conjunction with starter problem.

Both of these problems showed up regardless of whether car was in gear or neutral although the loose heat shields showed up more under way.

These may not be your problems, but the fact that it happens in P/R/N/4 is a strong clue that may make it easier to find the cause.

I am not sure about this, but if you can't get the torque converter plug out, perhaps it may be possible to flush the fluid out via the transmission cooler hoses? (I have not looked at this myself)

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5