Expert- what is the real difference between ATFs?

[lomez]

So....I believe that Dex (not VI), Merc V and T-IV are essentially interchangeable. Sort of in the way Mobil 1 5W30 is the "same" as Pennzoil Ultra 5W30 is the "same" as Castrol Edge 5W30. That is, they are not the "same"...but certainly meet the same specs. Of course not according to the manufacturer, who licenses the trademarked name though. Is that wrong? If so, why / how??

What about ATF+4. What is the difference there??

I mean, Redline has (basically) 3 fluids.
* A thick that replaces everything except ATF+4.
* One that replaces +4.
* One that replaces a thin fluid like WS or Dex VI.

Hope this isn't a dumb question. Looking for an education not a flame session.

 

[901Memphis]

Heres some info incase you want to read up before the "experts" chime in. Most of this info is from the experts though.

https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=530806&fpart=2

https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=3188949

https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2667388

https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=3189713

 

[95busa]

Once clutch engagement became computer controlled in transmissions, fluid type became extremely important. I would never use a "universal" type ATF in any of my transmissions. My later model fords require Mercon SP and Mercon LV respectively. They are not interchangeable, and some of the multi-spec transmission oils specifically state as such. Run a decent quality oil endorsed by the manufacturer and service regularly. The manufacturer even gets it wrong sometimes in reference to interchangeability. At one point Ford was saying Mercon LV could be used in Torqueshift transmissions calling for Mercon SP. Not so much- motorcraft resumed production of Mercon SP shortly after that proved incorrect.

 

[Wilhelm_D]

Originally Posted By: lomez
Hope this isn't a dumb question. Looking for an education not a flame session.

The Major ATF Families

Automatic transmission fluid is a hydraulic fluid that performs the functions of providing hydraulic pressure, transmitting torque, reducing wear through lubrication, cooling, maintaining cleanliness, and providing appropriate friction characteristics for friction surfaces.

Roughly speaking most modern ATFs can be divided into standard viscosity (Mercon V, SP-III) and low viscosity (Dexron VI, Mercon SP).

A further distinction is in the friction coefficient characteristics, which vary from Ford F type (no friction modifiers) to Chrysler ATF+4 (highly friction modified).

The trend is currently toward low viscosity fluids which are made possible by synthetic and semi-synthetic base stocks and improved VI modifiers. In the past the specifications assumed a drop in viscosity over time from shearing, so that new ATF was "thicker" than needed to allow for this.

There are also fluids designed for very specific applications such as CVTs which really don't fall into the classifications above.

 

[pbm]

I believe the universal type fluids can be used.
I have used Castrol Import Multivehicle ATF successfully in a Toyota Corolla.
I have used Valvoline Maxlife ATF successfully in a Hyundai Elantra.
I used Mobil 1 ATF exclusively in my Buick.

All worked great.

In my Honda Accord I stuck with Honda ATF because it was a known problem unit (BAXA). I was not impressed with the Honda Z-1's tendency to darken in only a few thousand miles. Because Honda had extended the warranty I didn't want to experiment but if I still had the car I'd be using Castrol IMV or Maxlife.

PS: Some have suggested that +4 fluid would work in my Hyundai (and Corolla) and that it's an awesome fluid. Maybe one day I'll try it.

 

[David1]

Originally Posted By: pbm
I believe the universal type fluids can be used.
I have used Castrol Import Multivehicle ATF successfully in a Toyota Corolla.
I have used Valvoline Maxlife ATF successfully in a Hyundai Elantra.
I used Mobil 1 ATF exclusively in my Buick.

All worked great.

In my Honda Accord I stuck with Honda ATF because it was a known problem unit (BAXA). I was not impressed with the Honda Z-1's tendency to darken in only a few thousand miles. Because Honda had extended the warranty I didn't want to experiment but if I still had the car I'd be using Castrol IMV or Maxlife.

PS: Some have suggested that +4 fluid would work in my Hyundai (and Corolla) and that it's an awesome fluid. Maybe one day I'll try it.



Did you ever try the Honda DW-1 when you had your HONDA?
Im told it has advantages over the older ATF Z-1

 

[Sierra048]

Do to all the clamor over the ATF/coolant mixture problems that were destroying the transmissions in the earlier 2nd generation Nissans, I swapped the Matic J in our Nissan with Mobil 1 synthetic ATF, yes the universal type. I was told that anything other than a gold-priced Nissan fluid would torpedo the transmission. As of right now, 40K later, the transmission shifts just as smooth as the day it was purchased and with absolutely no side effects.

 

[lomez]

So I still can't figure out why, assuming most all of the "thick" ATFs have the same viscosity......but some have more FMs than others, and some are conventional oil while others are group III......why would using a synthetic with all the FMs not work as well or better than anything else?

For example, why would using ATF+4 in place of say T-IV be a bad thing? It's the same viscosity. It has more FMs (wouldn't that be a good thing with zero downside?). It's group III instead of II. I'm probably missing some important issues or making incorrect assumptions.

Type | Viscosity | @ 40C | @ 100C
ATF+4: V204, 33.24 7.51
MercV: V205, 33.20 7.50
DexIII: V201, 34.70 7.70
Type F: V150, 36.00 7.20
DexVI: V145, 29.50 5.83 *1

Amsoil: V168, 38.90 7.60
RoyalPurple:V210, 32.50 7.50
Redline syn: V197, 32.50 7.20
Redline C+ : V213, 32.30 7.50
Redline Race: V177, 53.70 10.00

 

[antiqueshell]

@lomez:

The main reason they recommend manufacturer branded fluid is because the manufacturer tested their own fluid with enough conditions and miles to make sure it will shift the way they designed the automatic unit to behave. The other fluids that will meet the specs of the manufacturer will likely be fine but they might exhibit slightly different shift quality, even if that will not cause any mechanical issues or wear over the OEM fluid.

I have a 94 Accord, and I recently did a drain and fill with DW-1 the car previously had Z-1 in it. But next time I do a D&F I will be using Castrol Transmax Import Multi Vehicle ATF.

 

[Wilhelm_D]

Originally Posted By: lomez
So I still can't figure out why, assuming most all of the "thick" ATFs have the same viscosity......but some have more FMs than others, and some are conventional oil while others are group III......why would using a synthetic with all the FMs not work as well or better than anything else?

In general the better the base stock the better the ATF. However, the frictional characteristics of different specifications are not exact matches. It is not merely a question of quantity but quality - the friction characteristics are charted graphically and some, like the Chrysler ATF+4, have different “shapes”.

Originally Posted By: lomez
For example, why would using ATF+4 in place of say T-IV be a bad thing? It's the same viscosity.

First of all, they are not the same viscosity. The Brookfield viscosity of the ATF+4 does not line up with Toyota T-IV.

ATF low temperature viscosities

Second, the curve of the frictional characteristics of ATF+4 is different than other ATFs.

Here’s the short summary. Transmission manufacturers develop their ATF specifications without regard to the aftermarket. This is the same reason we have hundreds of oil filter specifications instead of two dozen.

If you buy a vehicle and it’s under warranty, it behooves you to use whatever is specified since paying for automatic transmission repairs is no fun. Generally the manufacturer can determine whether you used a non-specified ATF in the event of a warranty claim.

After it is out of warranty you can do as you wish. In many applications under normal conditions switching ATFs appears to cause no problems. For example, many dealers have used ATF+4 and its predecessors in Mitsubishi, Hyundai, and Kia transmissions with no apparent ill effects. A number of aftermarket suppliers have produced multi-application ATFs and purport to stand behind them.

Would it make sense for the industry to move towards some standardization?

Sure.

Is it going to do so?

I think it is unlikely at the OEM level, but the aftermarket appears to be moving towards consolidating similar specifications.

 

[pbm]

Originally Posted By: David1
Originally Posted By: pbm
I believe the universal type fluids can be used.
I have used Castrol Import Multivehicle ATF successfully in a Toyota Corolla.
I have used Valvoline Maxlife ATF successfully in a Hyundai Elantra.
I used Mobil 1 ATF exclusively in my Buick.

All worked great.

In my Honda Accord I stuck with Honda ATF because it was a known problem unit (BAXA). I was not impressed with the Honda Z-1's tendency to darken in only a few thousand miles. Because Honda had extended the warranty I didn't want to experiment but if I still had the car I'd be using Castrol IMV or Maxlife.

PS: Some have suggested that +4 fluid would work in my Hyundai (and Corolla) and that it's an awesome fluid. Maybe one day I'll try it.



Did you ever try the Honda DW-1 when you had your HONDA?
Im told it has advantages over the older ATF Z-1



No I never tried the newer Honda fluid...I stayed with the Z-1 but I added LG Red and an inline filtermag. The transmission was still good at 109K when I sold it.

 

[PandaBear]

Friction property is my main concern, viscosity not so much.

With the wrong friction property you get shudder and can kill the clutch pack (or if you misuse in CVT, your belt).

Luckily most transmission wet clutch can tolerate a huge range of friction property / fluid, and viscosity (temperature), so you are likely to get lucky with universal fluid. Unless you put Honda ATF (with zinc, which will plug some clutch material) in other brands, or non CVT fluid in CVT, you are likely to be OK.

 

[David1]

Originally Posted By: 95busa
Once clutch engagement became computer controlled in transmissions, fluid type became extremely important. I would never use a "universal" type ATF in any of my transmissions. My later model fords require Mercon SP and Mercon LV respectively. They are not interchangeable, and some of the multi-spec transmission oils specifically state as such. Run a decent quality oil endorsed by the manufacturer and service regularly. The manufacturer even gets it wrong sometimes in reference to interchangeability. At one point Ford was saying Mercon LV could be used in Torqueshift transmissions calling for Mercon SP. Not so much- motorcraft resumed production of Mercon SP shortly after that proved incorrect.


I say go to dealer and get what they say .

Transmissions are not like ENGINES...

Plus AT Fluid is not changed each 3k or 5k miles

so if you run the WRONG Fluid in your AT for say 30K miles it can cause some major damage.

If transmissions were like ENGINES and you changed the FLUID each 3k or 4k or 5k then It might be different.

I mean have you seen any New car says Factory filled Transmission with XXX after market brand???

Never

However sometimes the Engine oil on some cars will say Factory filled with Mobil 1
like the CORVETTE.

Stick do the dealer stuff..... trying to save 10$ or 20$ could cost you $1000s

Now, if you have a a old car and the transmission is leaking and you know somthing is wrong then I would say go ahead and try some MAXX LIFE or Castrol High Mileage... or Lucus Trans conditoner

or Shirt Trick.....

but if your doing a regular Service.... use the Factory fluid...

Most Certified techs will tell you.

It was different years ago.....

I remember 20 years ago you just put multi ATF and that was that.

but the Transmissions today have computers and they can go from manual shift to automatic via a push of a button.

Like my sisters SCION.... very cool car... and handles awesome.. not so fast but nice.

I would never put MULTI ATF Fluid in that.

no way.

 

[Lolvoguy]

Originally Posted By: Wilhelm_D
Originally Posted By: lomez
Hope this isn't a dumb question. Looking for an education not a flame session.

The Major ATF Families

Automatic transmission fluid is a hydraulic fluid that performs the functions of providing hydraulic pressure, transmitting torque, reducing wear through lubrication, cooling, maintaining cleanliness, and providing appropriate friction characteristics for friction surfaces.

Roughly speaking most modern ATFs can be divided into standard viscosity (Mercon V, SP-III) and low viscosity (Dexron VI, Mercon SP).

A further distinction is in the friction coefficient characteristics, which vary from Ford F type (no friction modifiers) to Chrysler ATF+4 (highly friction modified).

The trend is currently toward low viscosity fluids which are made possible by synthetic and semi-synthetic base stocks and improved VI modifiers. In the past the specifications assumed a drop in viscosity over time from shearing, so that new ATF was "thicker" than needed to allow for this.

There are also fluids designed for very specific applications such as CVTs which really don't fall into the classifications above.


Thanks for this post!!

I was afraid that running Mercon in my 07 Focus was going to cause a premature death of the trans. Everyone was preaching at me to spend twice the price for Mercon V as it was "recommended". From my internet research, Mercon V was just a syn version of Mercon (not necessary if doing regular changes.) So I just extract a few litres of fluid and pour more in every 10k kms or so. Car really loves it since I first got it last summer. The first swap I immediately noticed smoother changes.