Dexron IIE / Mercon ATF replacement in Jeep AW4 tranny

[Titanium]

Hi all – I want to buy and revive a 1988 Jeep Cherokee Laredo 4WD 4.0L, and found an old Chilton guide for it. It says that its Aisin-Warner AW4 automatic takes "Dexron IIE/Mercon" ATF.

This fluid is no longer available apparently, and there are now lots of numbers beyond II (2, not 11). What throws me is that Dex IIE is identified as a GM thing, not a Jeep/AMC/Chrysler thing (I think Chrysler was just buying AMC/Jeep in 1987 or so). Is there a universal successor for Dex IIE?

Is there anything about this particular AW4 transmission, or the Cherokee, that would call for a different choice than whatever replaces Dex IIE in GM vehicles? There's some info on the transmission here: https://www.novak-adapt.com/knowledge/aw4

Thanks.

 

[atikovi]

One brand of Dexron IIE: https://www.ravenol.de/en/product-r...atic-transmissions-1/ravenol-atf-dexron-ii-e/ but I would assume Dexron VI would be backward compatible.

 

[blufeb95]

I'd think that any Generic DEXIII/MERC would work, if you want overkill You could get Allison TES-295 approved fluid like Delvac 1 ATF, Alison Transynd, Shell Spirax S6 295, or BP Autran 295

 

[Oro_O]

I would use DexIII and not DexVI. They have different viscosities and the DexVI can cause shifting to be less than perfect sometimes. Not always, but I have personally experienced it in a couple DexIII/T-IV designed transmissions. Went back to the prior generation fluids and shifting returned to normal.

Dexro III is fully compatible with the II, and the same viscosity. It is sold under various names now as it is no longer licensed by GM. "Dex/Merc", Chevrom MD3, etc. Walmart sells the Valvoline blend of it for a good price (~$12/gallon last I recall).

The transfer case in it might spec DexII, also. You can use the Dex III there, too, if it does. I have a late 90's SUV with a Borg-Warner t-case and it still spec'd DexII.

 

[92saturnsl2]

No need to overthink this. Any Dex III clone fluid will work, or Dex VI.

The viscosity difference between Dex VI and Dex III may not mean much in the real world. I've always heard that in use, Dex III will eventually shear to a viscosity similar to that of VI. I've had no trouble running Dex VI in older vehicles that were spec for III, but I understand some folks' hesitation regarding the thinner viscosity.

 

[Zaedock]

I also recommend using Dexron III/Merc and used it in my '92 Wrangler when I had an AW4 in it.

 

[Oro_O]

No need to overthink this. Any Dex III clone fluid will work, or Dex VI.

The viscosity difference between Dex VI and Dex III may not mean much in the real world. I've always heard that in use, Dex III will eventually shear to a viscosity similar to that of VI. I've had no trouble running Dex VI in older vehicles that were spec for III, but I understand some folks' hesitation regarding the thinner viscosity.

I don't disagree w/you on that, and especially don't want to argue with a fellow Kentuckian (that often ends in bloodshed IME - I grew up around Louisville long ago). I think a few things are at play:

a) MODERN DexIII with newer base stocks is way more shear-stable than the old, original DexIII. So the "shears fast" is really a thing, but not as so much nowadays.

b) Some transmissions are pickier about this than others. So people who say they notice no difference are not wrong, and those who do notice a difference are not wrong, either.

Petroleum chemistry has gotten so much VASTLY better in the last, oh, say 15 years, that I would err on the side of caution and go with a DexIII. But no one is going to do damage choosing differently. @Zaedock above has real experience w/this transmission (I do not) so that's valuable input.

 

[blufeb95]

I don't disagree w/you on that, and especially don't want to argue with a fellow Kentuckian (that often ends in bloodshed IME - I grew up around Louisville long ago). I think a few things are at play:

a) MODERN DexIII with newer base stocks is way more shear-stable than the old, original DexIII. So the "shears fast" is really a thing, but not as so much nowadays.

I'd think a full synthetic DEX3 would probably not shear as fast, but the cheap stuff probably hasn't gotten any better than in the past, DEXRON III was already made with group II+ oils long ago, transmission fluid was really one of the first automotive fluids to bring hydroprocessed oils to the mainstream. If you want Dexron III compatibility and shear stability I'd look more into Allison TES-295 fluids, and probably redline D4 it's probably the highest PAO DEX/Merc fluid you can find, has an even lower Brookfield at -40 than the TES-295 stuff which is great in the north probably not so much a necessary figure to consider in Arizona.

 

[Oro_O]

... transmission fluid was really one of the first automotive fluids to bring hydroprocessed oils to the mainstream....

Well that's very interesting, makes a lot of sense and valuable comment to bring to the table.

I'm not an expert on petroleum engineering. Have a very solid background in both inorganic and organic chemistry (more so organic, so less helpful here). I can follow the chemistry and arguments to a degree, but do not hold myself out as an expert.

Relatively speaking, and based on what you said, if you look back to the mid-90s and the Dexron specs then, compare them to motor oil chemistry at the time: the ATF specs/performance blows the API standards away. Meaning, very marginal gain in ATF performance since then vs. the very big gains in engine oil performance. So that makes a lot of sense.

 

[ka9mnx]

Wal Mart branded SuperTech ATF is the Dex/Merc approved (only) fluid I use in my 2000 4Runner (trans and power steering). DO NOT use Mercon V. Many say Dexron VI will work but I too had concerns about the viscosity difference.

MAG 1® Automatic Transmission Fluid - Mag 1

mag1.com

 

[kschachn]

Wal Mart branded SuperTech ATF is the Dex/Merc approved (only) fluid I use in my 2000 4Runner (trans and power steering). DO NOT use Mercon V. Many say Dexron VI will work but I too had concerns about the viscosity difference.

Supertech ATF has no approvals or licenses.

 

[kschachn]

Hi all – I want to buy and revive a 1988 Jeep Cherokee Laredo 4WD 4.0L, and found an old Chilton guide for it. It says that its Aisin-Warner AW4 automatic takes "Dexron IIE/Mercon" ATF.

This fluid is no longer available apparently, and there are now lots of numbers beyond II (2, not 11). What throws me is that Dex IIE is identified as a GM thing, not a Jeep/AMC/Chrysler thing (I think Chrysler was just buying AMC/Jeep in 1987 or so). Is there a universal successor for Dex IIE?

Is there anything about this particular AW4 transmission, or the Cherokee, that would call for a different choice than whatever replaces Dex IIE in GM vehicles? There's some info on the transmission here: https://www.novak-adapt.com/knowledge/aw4

Thanks.

The correct licensed replacement is any fluid with a DEXRON VI license. I've been using a DEXRON VI fluid in my old Sienna for many miles, and I used it for years in my old BMW 530i. There is zero concern about the viscosity of this fluid.

Yes, it may be that new "DEXRON III" fluids are more shear stable, but the old ones were not. Therefore if the transmission operated fine on those then it will operate fine on the new license. Besides it's not that much of a difference.

 

[Zaedock]

I found the Dexron III licenses expired in 2010 or 2011. If I still had the ol' AW4 slushbox in my Wrangler, then I would run Dex VI without worry.

 

[ka9mnx]

Supertech ATF has no approvals or licenses.

Ok. Recommended For. Happy?

EDIT: "Meets Requirements"

 

[2EHA]

any red colored fluid will work. it’ll even work with human blood

 

[Zaedock]

any red colored fluid will work. it’ll even work with human blood

That is confirmed when I rolled and it took a bit of time to get me back over and we had to top off the tranny with whatever we could find.
Blood, sweat and tears are also good for the seals.

 

[Oro_O]

Blood, sweat and tears are also good for the seals.

Not as good as ester oil, and only as long as the wheel is spinnin' - ride a painted pony and let it turn.



Gotta love a group that can top the Beetles in the Grammys (1970).

 

[nthach]

AW4 is mechanically very similar to Toyota’s A34x series installed in countless 4Runner/Hilux/Tacoma and Supra/Cressida/Lexus models.

The Lexus version of such, the A341E must use Toyota T-IV fluid or the equivalent. I had one of those. With that said, I’ve ran Toyota T-IV(or Mobil ATF3309, which is the same) and Castrol Import Multi-Vehicle with success. I’ve tried MaxLife and it just didn’t feel “right” to me. Though, viscosity wise it’s close to sheared, used DexIII/T-IV.

 

[thescreensavers]

It is increasingly difficult to find DEXIII locally and from previous discussions on this topic, its most likely better to run DexIV then to run DexIII in 2021 as Dexron VI is back-speced for AT's that used Dexron III/Merc.

• Dexron fluids: Dex III/Mercon type fluids: Max cSt 7.5; shears down to 4.2 cSt under standard tests
• GM Dexron VI: Starting viscosity cannot be > than 6.4 cSt; cannot shear down to less than 5.5 cST under standard tests.

• Mobil 1 Dexron VI: Starting viscosity - 5.83 cSt, cannot shear down to less than 5.5 cST under standard tests.
• MaxLife ATF: Starting viscosity - 5.91 cSt, cannot shear down to less than 5.5 cST under standard tests.
• Redline D6 ATF: Starting viscosity - 6.4 cSt, cannot shear down to less than 6.1 cST under standard tests.

Shear testing is done using four tests; the Fuel Injector Shear Stability test, the Sonic shear test, the DEXRON®-III Cycling test and the KRL test. The KRL tests have been shown to provide the better accelerated shear tests, in which all of the above fluids have been subjected. Let's look at some of the Dexron III(H) and Dexron VI stats.

Dexron III(H) is 1.4 cSt higher at 100C than Dexron VI (Starting Viscosities@100C Dexron III(H) 7.3 cSt, Dexron VI - 5.9 cSt)

Shear Stability:
• 10k miles: Dexron III(H) - 4.5 cSt, Dexron VI - 5.8 cSt.
• >=35k: Dexron III(H) - 4.3 cSt, Dexron VI - 5.5 cSt

Dexron III(H) has dropped over 2.8 cSt while Dexron VI has remained stable with only a 0.4 cSt drop.

Dexron VI is superior in terms of viscosity stability. Friction Modification Stability: In Dyno tests, Dynamic friction coefficient change: Dexron III(H) -~ 3%, Dexron VI - ~ 0.05%. Dexron VI is superior in terms of Dynamic friction coefficient stability. Dexron III(H) uses older Anti-Oxidant and Metal Inhibitor chemistry. Dexron VI uses modern Anti-Oxidant and Metal Inhibitor chemistry. Dexron III(H) uses older Anti-Wear chemistry. Dexron VI uses modern Anti-Wear chemistry.

The major difference is that Dexron VI contains a more stable additive package and a better mix of base oils than did Dexron III(H). The minor difference is the starting viscosity but the Dexron VI shears much less than the old Dexron III.

I question any statement that says a 1.4 cSt difference in starting viscosity in a well functioning transmission will make a difference.

It was also discussed briefly that "Modern" DexIII fluids are better than the "OLD" DexIII fluids being tested(above) but, there has been no tests to either prove or disprove that.


On my 200k+ AW4 I did a full trans flush (~20 Qts) with DexVI with no ill effects. You can get 1Gal of DexIV for $14 at Walmart.

 

[Titanium]

its most likely better to run DexIV then to run DexIII in 2021 as Dexron VI is back-speced for AT's that used Dexron III/Merc.

You threw me there a bit. It's better to run Dex IV (4) or Dex VI (6)? You said Dex IV first, but then said that Dex VI is back-specced for Dex III, which makes me think it's the successor.

Thanks.