I called several oil makers yesterday and the day before yesterday and asked which ATF is the best for my 722.4 (17 years old, 305000 miles).

What do you think about these recommendations?



Mobil

Mobil Dexron VI ATF or Mobil 1 Synthetic ATF

My additional Q: Is the synthetic blend (Mobil Dexron VI) better than full synthetic (Mobil 1) in seal compatibility for 722.4?
Mobil: No. Since your car was built in the 90's, seal compatibility is not an issue with our full synthetic fluids. For cars built in the 50's or 60's, it can be an issue.



Pennzoil (Shell)

Pennzoil® Transmission Fluid

My additional Q: Isn't your Pennzoil Dexron VI better for my car?
Pennzoil: No. not for your car. Use Pennzoil® Transmission Fluid or other previous Dexron fluids such as Valvoline Dex/Merc and so on.



Valvoline

Valvoline DEX/MERC ATF

My additional Q: What about Valvoline MaxLife DEX/MERC ATF or Valvoline DEXRON®-VI ATF?
Valvoline: They are full synthetic. I would not recommend synthetic for cars with that age and mileage.



Castrol

Castrol Dex/Merc Domestic Multi Vehicle

(Interesting point: Castrol has Import Multi-Vehicle and High Mileage ATF which are somewhat more expensive than Castrol Dex/Merc Domestic-Multi Vehicle, but they recommended the cheaper one as the "best" fluid for my car.)

__________________
1992 300D 2.5 turbo diesel. 319 k miles.
124.128 chassis, 602.962 engine, 722.418 tranny.