I have a copy of "Factory Approved Service Products November 2001", published by MB USA, LLC. I pulled this off the Web, and I think the reference was from this site, but I don't have the URL.

There are TWO power steering fluid products specified in this document depending on model.

S, CL, C-classes: 001 989 24 03 10, and this is also specified for "Active Body Control Fluid" on these models

E,CLK, SL, SLK-classes: 001 989 88 03 (The power top, load leveling, and hydropneumatic suspension fluid specified for CLK and SL is the above "03 10" product)

The "88 03" product was used when a dealer resealed my steering box in 1992. It's on the invoice, and I was given a bottle with the remainder of what was not used, and I still have it, so I am going on what appears to be a reasonable assumption that the "88 03" product is what was used in models of my vintage.

Of particular interest - all cases where the "88 03" product is specified for power steering systems is accompanied by the following note:

"or an approved Dexron III ATF, see page 6"

Page 6 lists over a dozen Dexron III products, but since Dexron III is a GM spec, I can't imagine that any Dexron III is unsuitable even if they don't have specific MB approval.

Most advice on this forum specifically recommends NOT to use ATF, but his flys in the face of the MB recommendation.

Any comments or other information?

Duke

Duke:
I would think that there are cross over products that are compadable with auto manufactures recommendations. But it their is a question than I would say that buying from the source that produces the automobile may be the safest and best way to write in a valid warrenty, if for some reason damage should happen.

I want to do the power steering fluid & filter change when you get some time and we can hook up. We can do your 190-E first and let the 300-E cool down.

I will keep an eye on your post. I am intrested in seeing the response .

Sincerely
Bob Geco

Thanks Duke. That's been my point all along too. I've got the 2004 Approved Products List and it says the same thing. I totally respect those who have said Dexron is no longer compatible with older MB power steering units. If Dexron causes problems, I'd like to see some scientific evidence of it, not just a couple of anecdotal incidents. I've been using Dexron for 24 years in my 240D with no evident problems. So there is one anecdotal example that it does work.

Len
'83 240D 345,000 miles original owner

There are "hydraulic fluids" used in the heavy equipment industry, and chances are they are compatible with MB power steering systems. Most are mineral oil based and have a viscosity in the range of a 10W motor oil or 70-75 gear oil like ATF.

ATF is formulated with some "friction modifiers" (like the additives for clutch or cone type limited slip differentials) for good wet clutch action and may also have some antioxidants to increase temperature degradation. All hydraulic fluids should also have some anti-foaming additives.

The trouble with MB and many other manufacturers is that they often don't give generic specifications, but say use part number... whatever, which are usually very high priced. The aftermarket is of little help since their products usually say "okay with most imports" or something similar, but don't say anything specific except for the fact that apparently Honda/Acura models require a "special" formulation, and some commercial power steering fluids state they are specifically for Hondas, while others specifically state not to use in Hondas.

Most automotive seals are neoprene based, which has good resistance to mineral oil and good temperature resistance up to about 200F, so I don't see how there is anything "special" about power steering seals or why Dexron III could be detrimental.

Since I want to change my power steering fluid and filter, I'm trying to sort this issue out, and there seems to be little other than hearsay and anecdotal evidence, however, these statements in the MB Service Products list clearly indicate that Dexron III is okay for vintage power steering systems, and I am hoping to sort out the issue once and for all.

Duke