Dexron III + Friction Modifier = ATF +4 ?

[Torkenstein]

My 2001 Dodge Ram 2500 4x4 with Cummins I-6 diesel has the 47RE overdrive transmission specifying Chrysler's ATF +4 only. An independent diesel specialist shop drained, flushed and refilled with Dexron III / Mercon plus 20 oz ATP AT-203 synthetic friction modifier, claimed to provide equivalent performance as a highly friction modified ATF.

The manager said Dexron III has better "lubricity" and is preferred based on his long field experience. I must say the shift characteristics were smoother after the change, without the usual torque-converter lockup judder. However, the manager said on a later visit he has to document all future ATF changes for Chrysler 47RE transmissions with ATF +4 for warranty / claim purposes.

My conservative thought is to follow the service manual and not try to reformulate to lubrication specifications with off-the-shelf additives. Any practical advice is welcomed.

 

[MolaKule]

Quote:
My conservative thought is to follow the service manual and not try to reformulate to lubrication specifications with off-the-shelf additives.


You are absolutely right.

Have them remove the current fluid and refill it with ATF+4 at THEIR cost.

The independent shop and managers in general are uneducated in proper fluid chemistry.

 

[stchman]

Will this "manager" fix your transmission if something goes out?

 

[G-MAN]

Originally Posted By: Torkenstein
The manager said Dexron III has better "lubricity" and is preferred based on his long field experience.


The manager is full of you-know-what.

Tell him you'll run whatever he says so long as he signs a legally binding contract that says he will replace your transmission free of charge if it grenades.

 

[Jay1981]

This is a very common practice with quick lube places. I know, I used to deliver oil for a living. They buy Dex III and use whatever additive to make it +4, Dex VI,
Mercon V, etc. I suppose its probably ok or they wouldn't all be doing it, it would become too costly if everybody's trans blows up. That being said, I would rather change it myself so I know what's going in, or maybe take it to a dealer, as they *should* use the proper fluid.

 

[eljefino]

Would you buy 0w20 and add a precision amount of STP to make it 15w40? Nope? Same thing.

 

[chad8]

Originally Posted By: T4R
This is a very common practice with quick lube places. I know, I used to deliver oil for a living. They buy Dex III and use whatever additive to make it +4, Dex VI,
Mercon V, etc. I suppose its probably ok or they wouldn't all be doing it, it would become too costly if everybody's trans blows up. That being said, I would rather change it myself so I know what's going in, or maybe take it to a dealer, as they *should* use the proper fluid.


By the time your trans blows , the shop has no liability. It may only shorten the life by 20%, but you see it done all the time. You would attribute it to a normal wear out, but the "factory correct " or superior fluid is ALWAYS best.
It is still better than leaving old fluid in and may work just fine.
That is the issue. Its a [censored] shoot with [censored] fluids.
No matter what some guy making a profit off you says.

 

[EricF]

If I had to, I'd be more comfortable with the LubeGard version.

 

[bullwinkle]

The 47RE behind a Cummins is trouble prone with the correct fluid in it-ATF+4 isn't that expensive!

 

[NHGUY]

+4 has been around for what,15 years? No reason not to use it.Cant wait til +5 comes along...

 

[901Memphis]

Supertech atf +4 is probably cheaper than the Dex they put in it. Maybe you can do it yourself next time? Mityvac it.

 

[MolaKule]

Quote:
They buy Dex III and use whatever additive to make it +4, Dex VI,
Mercon V, etc.


There is no way one can convert a DexIII to a DexVI by using a conversion fluid.

I highly recommend NOT using any aftermarket friction modifier or conversion fluids.

You're playing with fire when modifying the static and dynamic friction coefficients of the ATF.

 

[askani79705]

Originally Posted By: eljefino
Would you buy 0w20 and add a precision amount of STP to make it 15w40? Nope? Same thing.


Or cutting 15w40 Rotella with MMO and calling it 0w20 Mobil 1.

 

[jake88]

No additive can be added to convert a Dex III fluid to anything else, no matter what an oil marketer says about it. Shops like to believe they can do this, as it simplifies managing their shops, but if they cannot handle complexity they will go under when the warranty period expires on all these new Ford-Getrag DCTs and new CVTs on the market.

Echo the above concern - If they don't want to fix it on their dime, then you can take it to a different shop and send them the bill. If they won't take care of you, file a complaint with Weights and Measures.

 

[Torkenstein]

Thank you all for the advice and comments that reinforce my gut feeling no shade-tree shop can blend complex lubricant requirements with an additive. I should have insisted on ATF +4.

That said, I am still leery of the 47RE trans behind a Cummins, as noted above, so even the OEM doesn't get it right all the time. The 2001 Ram diesel suffered from being at the mechanical-electronic control interface with Bosch VP44 injector-pump failures from low inlet pressure and trans failures from converter lockup noise.

These forums are a great resource to share and learn from our real-world experiences.

 

[ac_tc]

The 47re wont start to die immidiately like the
a604 "ultradrives" did.
The basicproblem was that the 604 simply sheared the [censored] out of dex due to the wrong friction coeficent..
So chrysler made a solution in a bottle atf+3 wich became atf+4 an for it´s time superior oil.
So dex wont kill your tranny but it will require a shorter oci and it may shift diffrently.
Get the dex out, the cummins loads this tranny enough even with
atf+4.

 

[ac_tc]

The 47re wont start to die immidiately like the
a604 "ultradrives" did.
The basicproblem was that the 604 simply sheared the [censored] out of dex due to the wrong friction coeficent..
So chrysler made a solution in a bottle atf+3 wich became atf+4 an for it´s time superior oil.
So dex wont kill your tranny but it will require a shorter oci and it may shift diffrently.
Get the dex out, the cummins loads this tranny enough even with
atf+4.

 

[meep]

I believe the 47RE uses similar control logic to the 41TE, 42RE, 44RE.... which at least in the earlier days was a little picky about friction properties. I've played with LG and it can make a Dex work right, but it's really picky on getting the mix just right. It can work.... but do you trust the guy that precisely measured out 2.25oz of fluid.....?

It would make me nervous, and I am one of those people that usually doesn't stick with oem. The only fluids I'll put in a late model chrysler/dodge/jeep is ATF +4 (castrol is my fav there) or Amsoil. Between the 2, I can't tell any differences in driveability.

 

[ac_tc]

"I believe the 47RE uses similar control logic to the 41TE, 42RE, 44RE"
The a604,41te and 42te used electronics to not just set shiftpoint but they also modulated the shift electronically, this was the reason for them to be picky of friction properties.
The 44-47re basically had an old torqueflite valve bodey that used a computer to set shiftpoints, not controlling shift quality.

But anyway...use+4

 

[Wampahoofus]

Originally Posted By: ac_tc
The 47re wont start to die immidiately like the
a604 "ultradrives" did.
The basicproblem was that the 604 simply sheared the [censored] out of dex due to the wrong friction coeficent..
So chrysler made a solution in a bottle atf+3 wich became atf+4 an for it´s time superior oil.
So dex wont kill your tranny but it will require a shorter oci and it may shift diffrently.
Get the dex out, the cummins loads this tranny enough even with
atf+4.


+1. This.

To add: +3 was vastly superior to Dex and didn't shear as badly, but was still basically a mineral base. It needed to be changed at about 40k miles tops or it would shear out. +4 was full syn and holds up MUCH better than even +3 (good for about 100k). Chrysler posted a study comparing them all in a 42LE...if only I could find it...