cardan differential oil

[weradus]

It is hidden somewhere on the forum but can't find it. What kind of oil do I require for the Differential of my 1966 230SL - Just found out it is rather low on it.

[jameshoward]

90 weight oil. Some use synthetics, some mineral. I use the latter. Castrol do a 90W in both, I seem to recall. I'm using Titan when I refill mine.

I assume you don't have a limited slip differential, as I think this needs a different oil. (If it's the original axle, your data card will tell you. I think there should also be a plate on the axle if LSD).

You probably know this but when checking the level or re-filling, do so with the wheels level, either from underneath in a pit, or put on stands as close to the wheels as possible. Taking an oil reading with wheels hanging down on the shocks will give you a false reading, because some of the oil will have gone into the axle tubes. Don't overfill.

[weradus]

Hi James,

No I don't know :-) I had some leakage and a friend (amateur mechanic who is more in to English cars) checked it for me and said it needed additional oil. How can I check the level  ?

Thanks Willem.

[jameshoward]

Willem,

You'll need a special (actually, not so special) sump plug spanner. It is a standard item in the car tool kit if you have one; you'll spot it at once. I''m afraid I can't remember the size; someone will pipe up with it, I'm sure, or do a search.

With the axle tubes level, so as if the car was sitting normally on the ground, remove the filler (as opposed to the drain) plug on the diff and place your finger inside. You should be able to feel the oil if the level is correct. You may have to bend your little finger in a little to feel it. If you can't it may need topping up a little. You'd need to do this with the axle tubes level again, or you will over fill. A pit would help, or lift the car on a ramp. If you haven't changed the oil for a long while, and you do need to go somewhere to find a ramp or a pit, it's probably worth chaning the oil for all the hassle. I seem to recall that the capacity is 2.5 litres. You could remove and check the breather whilst you're in there to ensure it's not blocked and thus allowing pressure to build up which may have something to do with why your levels may be low. Again, a quick search on the site will provide some answers. Look under the suspension thread and you'll see my post about the diff change. I think there are some pics there of the breather.

If doing it on your own, you may want to get one of those large syringe type items that are used for filling with fluids and which have a flexible pipe at the end. You can get them in any car parts shop for a few euros. It'll make life easier.

[weradus]

The local shop has 80-90W so called old fashioned cardan oil will that be ok you guess ?

EDIT: Ignore this post, found the proper oil - 90W for classic cars, ETA tomorrow afternoon.

[Jonny B]

The tool for the drain and fill plugs for the differential is 14 mm hex head. I purchased a socket with the hex head and it just fit in the access space.

[hands_aus]

Willem,

You'll need a special (actually, not so special) sump plug spanner. It is a standard item in the car tool kit if you have one;

My tool kit does not have the spanner mentioned.
Am I missing it?
Was it in all Pagoda model tool kits?

[Jonny B]

I do not believe the spanner with the 14 mm hex head was a standard item for the Pagoda tool kit. I did purchase one somewhere along the way, and have it in the tool kit bag, but more than one person has stated that it is not a part of the regular complement.

[jameshoward]

I do not believe the spanner with the 14 mm hex head was a standard item for the Pagoda tool kit. I did purchase one somewhere along the way, and have it in the tool kit bag, but more than one person has stated that it is not a part of the regular complement.

Oh. My car's tool kit came with one, along with the 2 small lubrication guns and a few key scanners. The car is quite original and I just assumed that was the case. Thanks for pointing that out.

[mbzse]

Oh. My car's tool kit came with one, along with the 2 small lubrication guns and a few key scanners../..

Hmm James, seems you are fortunate enough that some previous owner aquired the Supplementary Tool kit from M-B, and added the contents to your tool roll.
When bought new, the supplementary kit came in its own pouch, see pic attached. The black, angled tool to the left has the 14mm hex that fits to loosen the oil fill plug.
/Hans in Sweden

[Jonny B]

The supplementary kit is a rare find. The original price - $13.81!! I got a copy of the dealer list price page. The set I have does have the 14 mm spanner for the oil plug and differential plug

[jameshoward]

Hans,

Thanks. Another mystery cleared up. I have exactly the kit shown in your photo, and the other tool roll. Bits of each are in the main tool roll (hence the spanners are in there). I just use the tool roll with the useful bits of each roll in there.

Very grateful for the insight, though. I imagine the supplementary kit as shown is worth a tad more than the first owner (2 owners before me) actually paid.

Thanks again.

James

[hands_aus]

Thanks for the feed back
great info.