Toyota ATF T-IV vs T-II
08-25-14, 01:02 PM
#16
not sure if it is T-II , i guess it is , i just did a drain and refill with Dextron T-II who is still available over here and did the oil change , i measured the old oil and fill the same amount of T-II , i don't think it had a oil change before since its a low millage car 90K miles
do you advise to keep change the ATF with T-II or start mixing with T-IV ?
do you advise to keep change the ATF with T-II or start mixing with T-IV ?
09-08-14, 09:22 PM
#18
Pole Position
i just did a drain and fill on my 94 LS400 and the guy at Toyota said to use Dex III tranny fluid, he advised against the Toyota IV tranny fluid......said my older Lexus tranny wasnt spec'd for the newer Toyota IV fluid.....any thoughts guys??
Last edited by OMAHA; 09-09-14 at 10:33 PM.
09-08-14, 09:46 PM
#19
Pole Position
so i used Castrol ATF Import which is spec'd to replace T-IV.....also the Toyota guy called Lexus and he was told that Dex III was what my car was spec'd for and not to use the T-IV ATF......so now I'm confused....??
Last edited by OMAHA; 09-09-14 at 10:38 PM.
Type IV is the recommended fluid for the previous Toyota ATF fluid and is compatible.
09-09-14, 01:22 PM
#23
Lots of good info so far, but there's so much of it, it's a little confusing, so let me try to summarize the facts:
- original spec for ATF was Toyota type T-II ATF
- current spec for ATF is Toyota type T-IV ATF, still not synthetic
- Toyota type T-IV ATF is actually re-branded Mobil ATF 3309
- DEXRON is something else, Dextron is a common mis-spelling of DEXRON. DEXRON is a specification for ATF, manufactured by many vendors. MERCON is similar, but different, except when it's the same. Really.
- DEXRON of any type (II, III, IV) should not be used in your Lexus AT
- DEXRON III is fine to use for your Lexus PS fluid. MERCON too, I believe. Using ATF in your PS system is not common for most other brands of car, and that confuses many people, maybe even the tech guy at your Toyota dealer.
- DEXRON III is close enough to Toyota type T-IV (perhaps different only in additives?) that even Toyota says it's OK to use that in an emergency where T-IV is not available, but that then you should change it back out.
- As expected, there is plenty of suspicion that DEXRON is close enough to Type-IV and would work just fine, only that Toyota wants to make some $$ on the branding, in the same way that they sell Toyota branded motor oil, brake fluid, coolant, etc. Personally, I use Type-IV for ATF, but non-Toyota fluids for everything else.
- When you drain and fill, you only change ~2-3 quarts from a ~7 quart system, and subsequent drain+fills only dilute the remaining contaminants. Power flushing is never recommended by anyone who really cares about your car. A non-powered continuous flush has been done by many. It seems to not carry the dangers of a power flush, and takes about 12 quarts to almost fully replace almost all of the original fluid.
- So all of the aforementioned types can be mixed without too much worry if a mistake needs to be fixed.
Now to some of your questions:
If you have a choice between Type T-II and T-IV, I expect both are just fine and I personally would use the T-II if it was significantly cheaper, or if I had a spare case in the garage already. I know manufacturers always put a shelf life on everything for liability reasons at least, but I don't know of any chemical reaction that would be going on in the T-II bottle even if it is 15+ years old.
Regarding the 20 years on original fluid with low miles and absorption of water, I don't know, but ... wouldn't any moisture boil off and be vented whenever the ATF gets up to temperature? Are there any other reactions going on that could require replacement just based on age? I can believe motor oil will "age" but only because it is exposed to combustion. ATF seems safer. Kind of like differential oil - would you worry about 20-year old differential oil on a car that did 5k miles in that time? I wouldn't. Not knowing for sure, I'd think the ATF is between motor oil and diff oil on this one.
Answers? Corrections?
- original spec for ATF was Toyota type T-II ATF
- current spec for ATF is Toyota type T-IV ATF, still not synthetic
- Toyota type T-IV ATF is actually re-branded Mobil ATF 3309
- DEXRON is something else, Dextron is a common mis-spelling of DEXRON. DEXRON is a specification for ATF, manufactured by many vendors. MERCON is similar, but different, except when it's the same. Really.
- DEXRON of any type (II, III, IV) should not be used in your Lexus AT
- DEXRON III is fine to use for your Lexus PS fluid. MERCON too, I believe. Using ATF in your PS system is not common for most other brands of car, and that confuses many people, maybe even the tech guy at your Toyota dealer.
- DEXRON III is close enough to Toyota type T-IV (perhaps different only in additives?) that even Toyota says it's OK to use that in an emergency where T-IV is not available, but that then you should change it back out.
- As expected, there is plenty of suspicion that DEXRON is close enough to Type-IV and would work just fine, only that Toyota wants to make some $$ on the branding, in the same way that they sell Toyota branded motor oil, brake fluid, coolant, etc. Personally, I use Type-IV for ATF, but non-Toyota fluids for everything else.
- When you drain and fill, you only change ~2-3 quarts from a ~7 quart system, and subsequent drain+fills only dilute the remaining contaminants. Power flushing is never recommended by anyone who really cares about your car. A non-powered continuous flush has been done by many. It seems to not carry the dangers of a power flush, and takes about 12 quarts to almost fully replace almost all of the original fluid.
- So all of the aforementioned types can be mixed without too much worry if a mistake needs to be fixed.
Now to some of your questions:
If you have a choice between Type T-II and T-IV, I expect both are just fine and I personally would use the T-II if it was significantly cheaper, or if I had a spare case in the garage already. I know manufacturers always put a shelf life on everything for liability reasons at least, but I don't know of any chemical reaction that would be going on in the T-II bottle even if it is 15+ years old.
Regarding the 20 years on original fluid with low miles and absorption of water, I don't know, but ... wouldn't any moisture boil off and be vented whenever the ATF gets up to temperature? Are there any other reactions going on that could require replacement just based on age? I can believe motor oil will "age" but only because it is exposed to combustion. ATF seems safer. Kind of like differential oil - would you worry about 20-year old differential oil on a car that did 5k miles in that time? I wouldn't. Not knowing for sure, I'd think the ATF is between motor oil and diff oil on this one.
Answers? Corrections?
09-09-14, 02:46 PM
#25
Pole Position
i called Lexus today and the parts man said his technician said that T- IV can be used in '98 Lexus or newer and said to use Dex III in older models like my 94 LS......i honestly believe T-IV is better....my manual says T-II or equivalent....
Last edited by OMAHA; 09-09-14 at 10:59 PM.
09-09-14, 05:41 PM
#26
Moderator
The base oil is the same but the T-IV contains more over-based Ca-sulfonate and friction modifiers (FMs) to match the slip-controlled lock-up clutch system. I have a R&D report regarding this but it is all written in Japanese. I wish I had a good capability to translate it.
09-09-14, 08:10 PM
#27
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The base oil is the same but the T-IV contains more over-based Ca-sulfonate and friction modifiers (FMs) to match the slip-controlled lock-up clutch system. I have a R&D report regarding this but it is all written in Japanese. I wish I had a good capability to translate it.
Ok... so T-IV is not synthetic? Is there a synthetic that can/should be used in place of the T-IV or 3309 Oil?
09-10-14, 12:42 AM
#28
Moderator
There are some companies that sell their synthetic ATF claiming, "Compatible with Toyota T-IV". But as long as the T-IV itself is available, there is no reason for me to choose a non-genuine one. I prefer to use a genuine one too.
Having some connections with engineers of Toyota and related companies, I know how they are working hard and are strict to qualities and others. I relay on them and I have no reasons to use non-genuine liquids.