Differential whine on a MB123 200 auto

[Delicate Lady]

Looking for layman's method of detecting whether a whine is coming from the diff, wheel bearings,gearbox or someplace else etc.etc. My lady has the following symptoms, when I accelerate to about 80 km/hr there is a definite whine like noise which I hear and think is coming from behind when I am driving. Soon as i take my foot off the accelerator it disappears and appears again once I accelerate again. It's annoying. My layman friends have mentioned things like "pinion gear" , "crown bearing" , "propshaft" conking in so I would appreciate any views and advice from the esteemed members and readers of this forum as how one goes about detection. I have a 1983 MB123 200 auto - 240k on the speedo.

 

[MIW615]

Looking for layman's method of detecting whether a whine is coming from the diff, wheel bearings,gearbox or someplace else etc.etc. My lady has the following symptoms, when I accelerate to about 80 km/hr there is a definite whine like noise which I hear and think is coming from behind when I am driving. Soon as i take my foot off the accelerator it disappears and appears again once I accelerate again. It's annoying. My layman friends have mentioned things like "pinion gear" , "crown bearing" , "propshaft" conking in so I would appreciate any views and advice from the esteemed members and readers of this forum as how one goes about detection. I have a 1983 MB123 200 auto - 240k on the speedo.

From your description it sounds like "differential whine" this is where the meshing between the crownwheel and the pinion has become excessive. This is caused by wear in the diff and pinion bearings thus altering the mesh causing the whine. Only solution if this is the case is differential needs to be removed and overhauled

 

[Delicate Lady]

Ouch ! but thanks, not sure if this will be cost effective here in South Africa but I'm going to call around at the various MB dealerships or gearbox/diff specialists and hear what they will quote for an overhaul vs a second hand one. Can't imagine what it would cost - I am already shuddering at the prospect !

 

[MIW615]

Ouch ! but thanks, not sure if this will be cost effective here in South Africa but I'm going to call around at the various MB dealerships or gearbox/diff specialists and hear what they will quote for an overhaul vs a second hand one. Can't imagine what it would cost - I am already shuddering at the prospect !

If it's cost prohiitive, then just put up with the whine - buy a CD player and turn up the volume seriously a secondhand diff is the best deal if you can get one

 

[television]

You could of coarse check the oil level in the diff, or change to another grade

 

[Glenn Smith]

Change the diff oil, use a fairly thick say sae90, or a synthetic multigrade and add a dollop of moly grease, this will quieten it down no end.

 

[Delicate Lady]

Thanks all for the advice/comments, read also someplace the suggestion of introducing flaked graphite and another thread suggested sawdust - surely thats asking for trouble ? Apart from changing the diff oil it would appear from what the secondhand dealers quote vs the gearbox/diff rebuilders quote, the cheapest route would be to replace it with a secondhand one. Local breaker here can get me one for about R1000 fitted however with no guarantee. If it does'nt work he will replace it again or refund my money. Sounds like a fair deal.

 

[Delicate Lady]

Also as a matter of interest, how far could one push it, I mean driving around distance wise. With spring approaching here , the days will be warming up and I will be looking forward to those slow meandering Sunday drives into the countryside - I guess about 300 to 400 kms a round trip. Will I be risking it ?

 

[MIW615]

Also as a matter of interest, how far could one push it, I mean driving around distance wise. With spring approaching here , the days will be warming up and I will be looking forward to those slow meandering Sunday drives into the countryside - I guess about 300 to 400 kms a round trip. Will I be risking it ?

Bit of an open-ended question, but I wouldn't have thought there would be any problem