Q: Why Dexron III over Dexron II?

[paulo57509]

Perhaps this has been asked before, but if you wanted to flush/drain/refill/whatever your vehicle's ATF and your vehicle was originally spec'ed for Dexron II (because Dexron III did not exist at the time your vehicle was manufactured) and both Dexron II & III are available in the brand of your choice, which Dexron would you use and why?

I would go with Dexron III but I'd like to hear other opinions.

Oh yeah...and why would Redline offer both?

 

[exranger06]

Dexron III because I have never seen a bottle of Dexron II in my life. (Way too young.) I had no idea Redline sells it.

 

[PT1]

Because DexIII is better.

 

[Nick R]

I would use Dexron VI because it is back-specced to work with Dex II/III and is better. Personally I use Valvoline Dexron VI Full Syn ATF.

 

[prax]

Redline sells a Dexron II/Mercon fluid in addition to D4. It's called Synthetic ATF.

"The least used of all Red Line ATFs, we remind that all of our automatic transmission products are fully-synthetic, so be sure not to confuse this less versatile product with other more flexible products like D4 ATF, our most popular."

Anyway, I would also use Valvoline Dexron VI. Fully synthetic. That or Supertech since it's relatively inexpensive. Be sure to flush because you won't get much of a benefit if you mix it with Dex III/II.

 

[unDummy]

Some manual transmissions don't shift all that well with universal multivehicle ATFs. So, DexII synthetic ATF is a choice worth trying.

DexronVI is only back spec'd for GM vehicles, even though many will use it anymore any dexiii equivalent was used.

 

[AzFireGuy79]

Do you plan on going with redline? I have run both, the synthetic ATF and D4 ATF in a older suburban. It felt better on the D4. Granted this was in Arizona so the added viscosity probably had something to do with that. I like that the D4 is a GL-4. With non GM vehicles UnDummy makes a good point. I would not run the DEX VI. Not a good idea in non GM vehicles and some real old high mileage units.

 

[Ken2]

Nobody has made Dex-II for many years. No one is making official Dex-III any more, 'cuz GM no longer licenses it.

If you have a Honda that called for Dex-II, don't use Dex-III. Use Honda's own ATF or a near-universal fluid "recommended" for Hondas. The same thing might apply for Mercedes. In all other cases I know of, Dexron-III is the right fluid to use for transmissions that originally called for Dexron-II...unless there is a more modern product.

Dexron-VI is for ONLY GM's Hydramatic transmissions and certain GM Allison transmissions that have been tested with Dex-VI.

 

[440Magnum]

Originally Posted By: Ken2

Dexron-VI is for ONLY GM's Hydramatic transmissions and certain GM Allison transmissions that have been tested with Dex-VI.


From what I can gather, Mopar ATF+4 is probably a closer match to Dexron III in most regards than Dexron VI is. That is assuming the friction modifiers +4 includes for the Chrysler lockup TC clutch aren't a problem in the Dexron III application (they usually aren't).