1982 240D whining when driving

[Binnkin]

I wanted to preface this question by saying that it first started last November but disappeared during the winter months and has once again appeared.

The car makes a buzzing sound when accelerating. It sounds similar to making a "V" sound with your mouth that raises in pitch as you accelerate. The volume and intensity also varies. It periodically stops and starts again, but when it begins again it starts at a low pitch and raises. It will do this maybe 3-4 times until I hit highway speeds.

The sound continues when the clutch is engaged. The sound will also persist if the car is shut off while driving down the road. I find that it will also come back as Im decelerating but from a high to low pitch.

I was thinking that it might be the speedometer cable or instrument cluster, so I disconnected it from the transmission. The sound has continued to persist. I am going to check the fluid level in my transmission next, but I dont know if that has anything to do with the problem.

Any ideas would be greatly appreciated!

[Binnkin]

Since the noise is hard to explain, Ive uploaded a video.

https://www.youtube.com/watch?v=KAp88ScIUTY&feature=youtu.be

[barry12345]

The car is haunted. Actually my first impression was that it was a wind noise. My second thought is I would want to check the oil level in the differential.

This last thought is just a guess at best though. I really have not personally experienced a noise in a car quite like this one.

The not present when cold out is ringing some bells in my head. It is just nobody is home to pick up the phone apparently..

I even went back and listened to the video a few more times. That got me nowhere other than turning the volume up and down. The car does sound better with the volume reduced.

Since it does it the same with the clutch in or motor off just leaves me at a further loss. Hopefully some member will have dealt with or recognize this issue and post.

[Binnkin]

Could is have anything to do with bearings?

[Stretch]

I get the impression from the video that the biggest noise comes from applying power - is this the case?

If so then I'd be looking at the differential.

[sleepstar]

so high pitched... something definitely sounds dry somewhere. or is something rubbing on a moving part? did someone sneak one of those exhaust whistles into your tailpipe (sounds exactly like it!)

[Binnkin]

I think its the speed which causes the noise. Once I am up to whatever speed, I can shut off the car and coast and the sound continues.

Im trying to think of parts that move even when the car is coasting in neutral. Something in the drive train?

[bhowell]

low to high pitch seem to restart with your gear changes.

It's probably in your transmission. Is your ATF low? When was it changed? low or your filter clogged. Your pump and torque conerter sound starved for fluid.

I would have guessed driveshaft bearing or diff, but the pitch resets itself with gear changes.

Your car is pre-94 722.3 so you have a rear pump. This can explain the sound even when you are in neutral with speed.

[Binnkin]

Ive found that sometimes the noise does reset with gear changes and sometimes it doesnt.

Its a manual transmission, but I havent checked the fluid level yet. Is the only way to check this by unscrewing the 14mm hex on the side of the transmission?

[Stretch]

Fill plugs for both the gearbox and the differential are 14mm hex (if I remember correctly). Both are spill to fill.

[Binnkin]

Going to change the dif and transmission fluids today to see if that works some magic.

[cho]

.

this sounds exactly like diff noise...maybe you are out of lubrication
look for the metal shavings on plug and oil while changing....

.

[barry12345]

Differential noise was often described as howling. Whining is a reference more to the lady or child noise in transit.

[Zacharias]

Wow that is what I could call a HOWL.

If it were the diff, I would expect to make the sound in the winter months as well.

Driveshaft center bearing?

Let's trade. I have a kinda howl as well, but it only happens in the really cold conditions. Mine is like yours and a bearing rumble had kids.

[charmalu]

Maybe a bearing in the transmission failed letting the gears not mesh correctly. The early Datsun PU 5-spd had a problem with the front Counter Shaft Bearing failing. Had that kind of noise and replaced the bearings, and it went away. Haven`t heard of MB Bearings causing a problem, but ran on low oil could cause it.

I would also look at the center Support and Bearing.


Charlie