ATF +4 for a Dex III Application

[Winston]

Is ATF +4 OK for a Dex III application? Will it work better since it is synthetic? (Grp III I believe).

I have '95 Mitsu that calls for Dex II. I know Mitsu puts their SPIII in all tranny's they service. Since ATF+4 is similar to SPIII, shouldn't the ATF+4 be OK in a Dex III app? Are you following my logic? $4 for a synthetic ATF fluid is a pretty good deal.

 

[Ray H]

quote:

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Originally posted by Winston
Is ATF +4 OK for a Dex III application? ... Since ATF+4 is similar to SPIII, shouldn't the ATF+4 be OK in a Dex III app? Are you following my logic?

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Not really, Winston. How does any alleged similarity between SP III and ATF+4 translate to ATF+4 being an acceptable substitute for Dexron III? The friction modifiers of ATF+4 are different from those of Dexron III - more akin to those in non-synthetic ATF+3. If you want a universally available synthetic ATF suitable for Dexron III applications, get Mobil 1 Synthetic ATF.

 

[Winston]

If I take my '95 Dex II rated vehicle to a Mitsu Dealer they will put SPIII in it. They put SPIII in everything now.

 

[The Critic]

Well, its merely speculation that SPIII is identical to ATF+4. Play it safe and use SPIII or a Multi-Vehicle fluid such as Maxlife, Amsoil, or Pennzoil Multi.

 

[askani79705]

quote:

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Originally posted by Winston:
Is ATF +4 OK for a Dex III application? Will it work better since it is synthetic? (Grp III I believe).

I have '95 Mitsu that calls for Dex II. I know Mitsu puts their SPIII in all tranny's they service. Since ATF+4 is similar to SPIII, shouldn't the ATF+4 be OK in a Dex III app? Are you following my logic? $4 for a synthetic ATF fluid is a pretty good deal.

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What's wrong with putting DEX II in it if thats what the manual calls for? I'm with The Critic using a good multi won't hurt either.

 

[unDummy]

Yeah, $4 for a synthetic is a pretty good deal.
I bet that ATF+4 will work in place of many other OEM specs.

If your tranny isn't tired, go for it. It will shift smoother.
If your tranny IS tired, excessive smoothness equals excessive slippage which would be 'bad'.

 

[psudaytona]

Dexron and ATF+4 have different friction characteristics. +4 is much "slicker" and will grip less.


If you switch, just be very attentive to any sign the tranny doesnt like it.

 

[acewiza]

quote:

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Originally posted by psudaytona:
Dexron and ATF+4 have different friction characteristics. +4 is much "slicker" and will grip less.

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Huh?

Would you care to explain that comment in a little more detail? Or maybe just quote the 7176E spec in it's entirety so as to not muddy the water any further than it already is?

+3 and +4 are entirely backward compatible with the possible exception of seal issues WRT +4. I'm guessing this the same old synthetic leaks better than dino issue, but haven't seen anything definitive one way or the other on that yet.

[ August 15, 2006, 01:35 AM: Message edited by: acewiza ]

 

[Brett Miller]

Why not use Mobil 1 or Amsoil?

 

[Winston]

quote:

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Originally posted by Brett Miller:
Why not use Mobil 1 or Amsoil?

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Just pinching pennies. M1 is about $6 per qt. ATF +4 can be had for less than $4 per qt. For a 10-12qt tranny flush it adds up.

To me it stacks up like this.

Chevron Dex III $3/qt (Grp II+ base stock)
ATF +4 $4/qt (Grp III Base stock)
M1 $6/qt (Grp IV Base stock)
Mitsu SPIII $7.50/qt (Grp III blend?)

 

[The Critic]

Walmart DexronIII(H) and Lubegard Platinum... $3.00/qt.

 

[psudaytona]

quote:

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Originally posted by acewiza:

quote:

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Originally posted by psudaytona:
Dexron and ATF+4 have different friction characteristics. +4 is much "slicker" and will grip less.

---

Huh?

Would you care to explain that comment in a little more detail? Or maybe just quote the 7176E spec in it's entirety so as to not muddy the water any further than it already is?

+3 and +4 are entirely backward compatible with the possible exception of seal issues WRT +4. I'm guessing this the same old synthetic leaks better than dino issue, but haven't seen anything definitive one way or the other on that yet.

---

Ok, Dexron generates a higher amount of friction in things like the clutch friction plates. This was proven when chrysler dodge first said it was OK to use Dexron II in the case that ATF+(7176) was not available. However, they found out that it caused too much friction in the clutch packs and led to the early wear of those units. This problem was especially bad for the 604 which heavily depended on clutchpacks even more so than the previous a413 transmission. The higher amount of friction caused the clutch packs to send data to the TCM that it suffered a problem at clutch application, so the computer ordered the packs to cycle and try again. All this extra work caused the clutches to wear out and cause overheating of the fluid.

ATF+3 AND +4 have the same friction characteristics. They are slicker than Dexron II because when used in the same trannies, they caused less friction in the packs and allowed the true data to be sent to the computers.

Many dodge owners use Dexron II on purpose in their 3 speed autos used in racing, reason being the higher amount of friction leads to less slipping in gears and a crisper "sportier" shift. The downside to this is quicker clutch(and sometimes band) wear.


As for the leak problems, it has been documented by chrysler engineers that certain older autos will suffer problems due to seals made of materials not fully compatible with the new synthetic base. However, that being said if someone were running the 4 speeds, I would say whole heartedly switch to +4 because the added protection it will offer is more than a justification of the slight risk of leaks and the higher cost of the fluid.
http://www.allpar.com/mopar/transmissions/fluids.html

 

[unDummy]

There aren't too many good Dexron II fluids. This is, IMO, a pathetic obsolete spec, easily superceded by III-h and Mercon-V.

I also wonder why every ATF+4 discusion ends up linking to the allpar site. This isn't a 'can I use dexron in my ATF+ transmission?' thread! It is a "can I use ATF+ in my Dex tranny".

The thread starter does NOT require SPIII. So, he doesn't need to use it.

Winston, use whatever fluid you want. I would minimally use a blended synthetic MerconV or multivehicle fluid.
I wouldn't move too high up on the fluid expense on an 11 year oil transmission. You haven't mentioned mileage, condition, transmission type, or previous maintenance history.
Depending on the transmission condition, I would probably just use ANY DexronIII-h simply not to wa$te money on a transmission in unknown condition.

 

[psudaytona]

I would guess the reason ATF+4 convos tend to link to allpar is because its a chrysler fluid, and allpar.com is the best source of info on these cars and their trannys on the net.

The "dex in my atf+" POV vs the "atf+ in my dex" is actually the same argument. I wasnt trying to tell him that its the same thing. I am just saying that the same problems that plague the "dex in my atf+" folks are the same as "atf+ in my dex".

A tranny built to expect Dexron is expecting a fluid which will grip better than ATF+4 will.

And Dexron III suffers a 40% sheer in the 20 hour KRL Shear Test, while +4 only 10%. So in that I would say +4 is a much better fluid. Wouldnt be a bad choice so long as severe slipping doesnt begin.

 

[Brett Miller]

Pennzoil Multi-Vehicle would be a good choice.

 

[acewiza]

I cannot find any information detailing exactly what is the +4 seal issue in older cars. They probably don't know exactly what it is because it is the same issue that crops up with synthetics in older equipment, be it ATF, motor oil, gear oil, whaterver. Put it in a high mileage and/or older vehicle with marginal seals and guess what? IT LEAKS! Duh.

 

[unDummy]

Also note that SPII(dexronII/III) was superceded by SPIII and even back-TSB'd for certain applications to cure issues. This is why dealers will toss SPIII into everything. It works!
So, I wouldn't even worry about the 'too slippery' hearsay. You might actually benefit from it performance wise.

 

[Winston]

Thanks Undummy, you understand my question.

My vehicle has been owned by me since nearly new (15k). It now has 165k and runs like new. I have done a few tranny drain and top-ups. Had it flushed by the dealer once (who put in SPIII). I have used cheap Dex III, but lately have used M1 since I had a bunch that I intended on using for a Volvo tranny flush, but sold tha car before I got around to it.

So, ATF+4 is more slippery than Dex III. That does not seem like a good thing to me. I use it to tow sometimes. I will probably stick with M1. I plan on keeping the car a few more years (12k per year)

 

[Whitewolf]

psudaytona is correct. The friction is different and whilst it may be fine for it's intended application it is not tailored for GM applications. If you want a better fluid than your DEXRON-III try DEXRON-VI, there is plenty of information that you can Google regarding that upgrade and from what I can see it's probably one of the best fluids around right now