Diff Whining SLK 230K

[daveandfleur]

I've had a droning noise for some while (ruled out the wife as it still occurs when she's not there!). Was hoping it was a wheel bearing but the MOT test last week showed no wear or noise. The tester took it up the road to give me an opinion and in his view it was worn diff bearings which he reckons are a common weakness. Not seen this mentioned anywhere else but I feel he is right, it's that sort of noise. Car has done 115,000 miles with full main dealer history. I've tried changing the oil using the correct synthetic but no improvement.

Has anybody else heard of these failing? Any ideas for repair/replacement/likely cost? It's liveable with for now but will no doubt get worse with time.

Thanks
Dave

 

[nick mercedes]

I've had a droning noise for some while (ruled out the wife as it still occurs when she's not there!). Was hoping it was a wheel bearing but the MOT test last week showed no wear or noise. The tester took it up the road to give me an opinion and in his view it was worn diff bearings which he reckons are a common weakness. Not seen this mentioned anywhere else but I feel he is right, it's that sort of noise. Car has done 115,000 miles with full main dealer history. I've tried changing the oil using the correct synthetic but no improvement.

Has anybody else heard of these failing? Any ideas for repair/replacement/likely cost? It's liveable with for now but will no doubt get worse with time.

Thanks
Dave

Diffs are normally strong in SLKs, are you sure it's not the wheel bearings?

NB I've got 2 or 3 SLK diffs so if you do need one...

But it's normally always the wheel bearings.

The big problem MB diffs are the C180/190E units and some of the diesel ones.

 

[evdok]

I've had a droning noise for some while (ruled out the wife as it still occurs when she's not there!). Was hoping it was a wheel bearing but the MOT test last week showed no wear or noise. The tester took it up the road to give me an opinion and in his view it was worn diff bearings which he reckons are a common weakness. Not seen this mentioned anywhere else but I feel he is right, it's that sort of noise. Car has done 115,000 miles with full main dealer history. I've tried changing the oil using the correct synthetic but no improvement.

Has anybody else heard of these failing? Any ideas for repair/replacement/likely cost? It's liveable with for now but will no doubt get worse with time.

Thanks
Dave

Get a second opinion

 

[daveandfleur]

Thanks Nick and evdok

I'll certainly get some more opinions before I carry out any work. Perhaps it will become more obvious where it is coming from as it deteriorates. Its merely annoying at the moment and I can live with it until summer, not having a garage I'll be more inclined to do such work then. It does sound like the diff to me though. If that does turn out to the case how much would you want for a diff Nick?

Dave

 

[nick mercedes]

Thanks Nick and evdok

I'll certainly get some more opinions before I carry out any work. Perhaps it will become more obvious where it is coming from as it deteriorates. Its merely annoying at the moment and I can live with it until summer, not having a garage I'll be more inclined to do such work then. It does sound like the diff to me though. If that does turn out to the case how much would you want for a diff Nick?

Dave

Low milage one £150 inc shipping.

I doubt you'll need a new diff though, almost always turns out to be a wheel bearing.

 

[Adam230K]

I've had a droning noise for some while (ruled out the wife as it still occurs when she's not there!). Was hoping it was a wheel bearing but the MOT test last week showed no wear or noise. The tester took it up the road to give me an opinion and in his view it was worn diff bearings which he reckons are a common weakness. Not seen this mentioned anywhere else but I feel he is right, it's that sort of noise. Car has done 115,000 miles with full main dealer history. I've tried changing the oil using the correct synthetic but no improvement.

Has anybody else heard of these failing? Any ideas for repair/replacement/likely cost? It's liveable with for now but will no doubt get worse with time.

Thanks
Dave

Hi Dave,

A few months back my diff went boom on my c230K and i replaced it with a second hand differential from Dronsfield mercedes who charged me £130 for a second hand like-for-like differential. The diff that they've given me developed a low pitched whine after 5k miles, but i've been told by several mechanics (mostly mb specialists who know what they're saying) that it has a long way til it actually becomes an issue (at least 20k-30k miles). I've also covered 7k since i've changed it, and its so damn nice, my old one used to bang alot and make loud noises.

Just turn up the music, thats what i do.

 

[bigstuff]

it might be the propshaft bearing .it known to cause the droning noise on a lot of mercs

 

[daveandfleur]

it might be the propshaft bearing .it known to cause the droning noise on a lot of mercs

Oh no, not something else to look for! Does anybody have any ideas how to pinpoint this noise, bearing in mind that the wheel bearings are making no noise when spun by hand?

Thanks again for all the advice folks. At least a used diff isn't too expensive. Sounds like they are not infallible, assuming a c230k has similar diff.

 

[BlackC55]

Drive it on a straight rd.

Stay in a low gear and accelerate. Then lift off. Is the whine worse when you do?

 

[daveandfleur]

Drive it on a straight rd.

Stay in a low gear and accelerate. Then lift off. Is the whine worse when you do?

Thanks. Tried this and it doesn't seem to get worse, although its hard to hear it over the engine when revving. Noise is most noticeable at around 45-60 and when slowing down although always present to some degree.

 

[BlackC55]

I would not suspect the diff then. It needs a proper look at.

 

[daveandfleur]

I would not suspect the diff then. It needs a proper look at.

Thanks again. I'm in Sussex so if I'm ever down your way I might pop it in for an opinion. No urgency as it's only mildly annoying at the moment.

Cheers
Dave

 

[BlackC55]

Thats fine. Pop in whenever you like and I will run it up the road with you.

 

[mark999]

I have the same faint whine on my SLK. Changed the diff oil without effect. Mentioned the noise to the guys at Autoelite in Hull when they fixed the roof. They think its the propshaft bearings as the noise disappears when you take the car out of gear.

 

[BEJ]

I had this on my SLK. I think it was the pinion bearing. Only occurred when accelerating between 50 and 60 mph.
Seems to have disappeared now, though I don't know why, but I'm not complaining.
Still have an oil leak from the pinion oil seal, but MB dealer says to ignore it as it is only minor.

 

[R W]

Dave
I had a noisey diff in my 124 yrs ago & I bought a second hand one, this was noisier than my original, but I kept it for a month for a small fee, to run the car till I repaired mine.I had in mind a full rebuild, but in fact all it needed was the front pinnion bearing. It would have been an easy cheap fix. I had all the bearings changed while the diff was out & it ran perfect for thousands of miles.

 

[johnsco]

If it is a diff bearing that's a bit noisy - It will probably run for a very long time before you need to take urgent action.
If it does become urgent, it will tell you about it loud and clear.
The noise will probably be horrendous.