rusty_one90

hello.
mb forum in Finland canīt help me so I hope you guys can help me.
my car: mb 190e 2.6 5speed manual.
i have whining noice at around 60km/h or about 35-40mp/h
its not get any louder in higher speeds, actually it dissapears or cant hear it anymore.
its loudest when you press gas pedal slighty.
hope someone can help me!

these are all parts i have changed.
- differetial ----> same whining..
- old diff with new bearings ----> same whining
- center support bearing( febi ) ----> same whining

what i should do next?

190Efan

If it's possible for you to do, try posting a video of your car making the winning sound. That will better help members in identifying the whine to help you correctly diagnose the problem. My guesses at this point without the video would either be a bad wheel bearing or a transmission issue. BTW, how many miles are on your car?

dolucasi

You have done all the right things with the differential swaps. My 2.6 manual also makes a whining noise at high speed, if I let up on the gas (so no load on the diff, or reverse load on it).

I also have quite a bit of backlash. I'm one bolt away from removing a newer diff with a 3.07 diff ratio at the JY. Will go back to remove it today.

Diff wear is normal on a 2.6 manual. My backlash started at 100K miles.

Now yours is a bit different and you have already done the diff swap. So like 190Efan suggested maybe post a video.
I wonder if yours is a transmission issue? How does the trans feel?

rusty_one90

its very hard to get that sound in video but i will try...
car has just over 388 000km / 240 000miles.
transmission working properly i guess.
those wheelbearings are next what i will do. it just not make sense that bearing sound changes according to the load and not like usually when cornering.
i have listening rear end with stethoscope when car is on jack/car lift but nothing because no load I think.
I'm very sure that diff is not a problem because 2 diffs and one of them with new bearings and exactly same whining.
you can hear whining even when clutch is pressed but then its not very loud.

and sorry if my english writing has some "errors"

dolucasi

Hmmm, see if you can locate if the sound is from the clutch/transmission area. Throw-out bearing comes to mind.
Is the clutch/transmission original without work done on either?

I suppose you can put a wireless microphone in different locations to isolate the general area.

rusty_one90

there is video with that sound.
https://youtube.com/shorts/tCR_EvSYZsc?feature=share

190Efan

Thanks for posting the video. I definitely heard the whining sound you're referring to. It's kind of hard for me to decide where the whining is coming from not actually riding in the car. I'm inclined right now to think it might be a bad wheel bearing because I'm also thinking that if it was the transmission, you'd hear it at the lower speeds but you say you're only hearing it at the higher speeds. A bad wheel bearing can have a roaring sound like what you're hearing at higher speeds and be quiet at lower speeds. Of course anything and everything is possible. I'm inclined to rule out the differential as Dolucasi explained as well. Where does the whining sound sound like it's coming from inside the car? Does it seem to be on just 1 side or the front or the back of the car? Maybe if you can figure out where the sound is coming from that'll help to determine where the problem might be even though sound does travel.

dolucasi

Tend to agree, if it is only peaking at a certain road speed and going away at higher speeds it either is in the front (wheel bearings etc) or past the transmission in the rear.

If you had excess to a dynamo, you can put the car on it and decide if it is front or rear, and since the car is stationary you can even isolate the sound rather easily.
Probably worth paying someone to use their dyno for 10 minutes. BTW, the mercedes dealerships in large markets in the US have dyno's. I had mine tested for emissions 5 years ago at the local dealership.

190Efan

I think using a dyno is a great idea. That'll provide the chance to walk under the car so you can try to isolate the whine to figure out where it's coming from and hopefully diagnose the problem. I have to say it sure does sound like some of the bad wheel bearings I've heard in the past. Given the mileage on your car it wouldn't be a shock if it was a bad wheel bearing.

rusty_one90

I'm going to replace rear wheel bearings next. sound is not clearly left or right but in rear axle anyway.
Winter is coming and i will do whole rear axle rebuild anyway. if that doesn't help then I will go in dyno and figure out where the fu*k that noice is coming.
I will update in here then if those wheel bearings help.
but if someone have any ideas where that sound comes, please tell me.

190Efan

Sounds like you have a plan. Let us know how it sounds after the rear wheel bearings are replaced because based on your video, that seems the most likely culprit as of right now.