Can anyone suggest a correct synthetic ATF for '90s era Mercedes-Benz 722.3 4spd automatic in a 500E?
It sounds like the current widely used standard isn't technically ideal for this older auto 'box that isn't computer controlled.
I found this good info posted elsewhere but would like to know what the BITOG members suggest.
Watch out for that "should be used" and "can be used" thing. For the newer 722.6 transmissions, MB says the latest fluid (236.14) "should be used" for older applications (i.e., early production 722.6 in the late 1990's) that originally called for for 236.12 or 236.10. Problem is, the .14/.12 spec is a low viscosity fluid, while the older .10 spec was for a normal (thicker) viscosity. MB says the thin stuff "should be used", but I don't agree. They recommend thin fluid for fuel economy, which is not my priority. The newer stuff is not always better!
Again, this is for newer MB transmissions, not our 722.3's in the 500E, but you get the idea.
And
The old Red Line Dex-II formula is no longer available. Red Line D4 or High Temp are the Dex-III replacements which will work well in a 722.3/.4/.5 transmission (the D4 can be used in the 722.6 as well). DO NOT use Red Line D6, which is the lower-viscosity Dex-VI. I am now using D4 or High Temp in all my cars. I haven't been able to find it for any less than approx $44/gallon ($11/qt) with free shipping, so if anyone knows of a cheaper source, please share!
Amsoil ATF (the current formula, anyway) is also a good Dex-III fluid.
And
Brief Discussion on the subject of ATF oil for 722.3 / .4 / .5 gear
These transmissions were built at that time for use with "ATF IID" developed oils.
It has already been noted several times that, for example, ATF III contains something "aggressive" and can dissolve the brake bands, which leads to slip when shifting.
Thus, I am using standard ATF IID (3 € / liter from Addinol) and I am very satisfied with the ATF IID from Addinol Oils Germany.
My automatic gearbox is 15 years old...Under the hood, you will find a 300hp AMG engine in my car... And the "unfortified" ATF IID is plenty for the job!
Oils from 236.10 and 236.14 service sheets are meant for transmissions with electronically controlled converter clutch (Küb) plate clutches and brake bands, ie from 722.6 and up.
These transmissions have special requirements on the coefficients of friction of the oil, therefore, the requirement is for "thin" oils.
Therefore, be sure to look when buying oil for the following approvals:
236.6 ( list of approved oils ) or 236.7 ( list of approved oils )
Are any of these ATFs correct?
http://www.redlineoil.com/product.aspx?pid=54&pcid=9
http://www.amsoil.com/shop/by-product/tr.../?code=OTFQT-EA
https://www.motul.com/system/product_descriptions/technical_data_sheets/2788/original/Dexron_III_TDS_(GB).pdf?1302206858