after few things that I have been dealing with, I figure it's time fro the diffy oil.
Any particular brand of oil or the mercedes oil will do?
Can somebody please tell me the torques for the fill and drain plugs and if there is anything important before I give it a go?

thanks for your time

ACM

make sure you take the fill plug out FIRST! if you can't get the fill plug out theres no reasont to take the drain plug out. Spray the bolts with some penetrating oil multiple times a few days before you intend to change it and it will make the bolts much easier to get out. I used 80w90 even though it calls for 75w90 because I couldn't find 75w90 at the autoparts store. Mobile 1 synthetic is the best fluid IMO, i'm sure MB fluid is good too (but over priced)

A location filled in on your profile would help alot for a question like this. The weight you should use is climate dependent.

Have a great day,

thanks for your responses so far.
i live in New Orleans, but I do not see how is that related.
Do you mean that I should choose a higher viscosuty oil in a hot place such new orleans?
Thanks

Yes, it makes a difference just like engine oil weight is determined by climate.

In your case 80W90 or 85W90 will be best. Brand is not that important, but I would not use a store brand. I would use any of the oil company brands.

Good luck,

37 ft-lbs for both the fill and drain plugs.

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95 E320 Cabriolet, 159K

Make sure it's a "GL-5", and 80W-90 is the common viscosity, which is fine for your climate.

Duke

Is there a problem with running a GL-4? I think that's all I could find and have been running it in my ponton and my 240D fpr several years. Doesn't seem to be a problem yet.

Len

this is strange!
The MB dealer told me that does not have differential oil and he reccomended to just buy a good brand from an auto parts shop!!!
He said that a Hypoid (is this a particular brand or...) gear W90 is the right oil.

Both filler and drain plug he said 50Nm = 37ftlbs.

BTW thanks for your help guys

1984 300d Diff Remove Fill Plug First, Use 14 Mm Allen Socket With 2 Ft Extension To Remove Drain Plug, Fill With Auto Store 75-90 Wt Diff Oil Up To Full Plug Level

I haven't seen straight 90W gear oil in I don't know when.

As mentioned above, 80W90 is common today.

I run 80W90 in the winter; 80W145 in the summer.

Where I live, winter is really nothing more than a "cooling off"....temps stay below 90F.

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'91 300-SEL

GL-5 gear oils are specifically formulated with EP additives for hypoid axle gears. I don't know of a manufacturer who recommends anything less than a GL-5 for a hypoid gear axle.

GL-4 gear oils are usually satisfactory for transmissions, or transverse drive train transaxles whose final drive is a big helical gear set rather than a hypoid.

Gears oils are always specified by BOTH SAE viscosity and GL-number; 80W-90 GL-5 mineral oil-based products are commonly available and are the usual choice unless you live in the arctic or the tropics. Synthetic-based GL-5s are also available and usually carry an SAE viscosity rating of 75W-90.

My recommendation is that you drain your axle and replace the oil with 80W-90 GL-5 at the earliest opportunity. You should find several brands at any auto parts store.

Duke

Here's what my bottle says - multi-purpose hypoid SAE 85W90 gear oil API/GL-4, a light duty gear oil with extreme pressure additives perfect for auto, truck and bus standard transmissions and differentials requiring API/Gl-3 and GL-4 oils.

My 240D manual only calls for Hypoid gear oil 90W or 85W90. No mention of any GL rating.

Len

Fluid for a differential must be a hypoid gear oil. The rear end is one of the few gear applications where sliding is the major action of the contacting gear set.

I have no data against GL-4, but since I personally have the habit of using GL-5 in all automotive differentials, and I've always seen GL-5 specified by auto manufacturers, so I too suggest using a GL-5 grade.

Since the bottle says "...perfect for applications requiring GL-4", it would help to know what your differential requires.

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95 E320 Cabriolet, 159K

okay here is the last question that I have for the rear axle:
I do not think I have a limited slip differential (i sae some diffy oils specially made for limited slip), but again I am not 100% sure.
1988 300E w124.030
What do you guys think?