The owners' manual for my 83 240D calls for ATF. I have flushed and filled with ATF, swapped out the filter, it seems very happy. It has no malfunction or strange noises, so I didn't add anything to the ATF during the R&R maintenance.

For my wife's mini-van (making growling/squeaking noises in the power steering), I swapped out all the power steering fluid with new fluid and then added about 20% Marvel Mystery Oil (MMO) by volume.

The noise immediately went away, and there are no leaks. Everything else seems to be normal.

Sincerely,

Packman

My research noted that MMO is composed of:

70% Light Aromatic Oil (Pale Oil)
- It is a Naphthenic Oil (as is power steering fluid), so while it oxidizes faster than a Paraffinic oil, it does clean and dissolve sludge and carbon well and cleans up after itself from any oxidation. serves as base oil as well. [Naphthenic oils have more solvency and are more polar (they are attracted to metal more), but oxidize faster.

29% Mineral Spirits
- Cleans Varnish very well. General cleaner. Also acts as an antioxidant.

38 parts per million (ppm) Boron
- AW/EP agent, friction reducer, antioxidant

900 ppm Phosporous
- AW/EP agent

1/2% 1, 2 ortho-Dichlorobenzene
- EP agent as it interacts with Iron to form an Iron chloride barrier under any ZDDP or other AW additives. Also very good cleaner/solvent, and friction reducer

1/4% 1, 4 para-Dichlorobenzene
- EP agent as it interacts with Iron to form an Iron chloride barrier under any ZDDP or other AW additives. Also very good cleaner/solvent, and friction reducer

Oil of wintergreen - for the scent
- Not just for the cent, is also a cleaner. may aid lubricity.

Red Dye - for the color
- well this one just colors the stuff

__________________
83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!