Old Mitsu A/T with Mobil 1 - No good?

[Winston]

I was on another board and there is a guy who has been having a lot of troubles with his tranny since he did a complete fluid change over to Mobil 1 Synthetic ATF. He kept getting a high AT temp light and then he would remove the pan and find a bunch of gunk in it. He cleaned the pan about three times in one year. Finally he sent in a sample for analysis and got this. The mfg recommeded fluid for a '90 Mitsu is "Dexron" or equivalent. Back then they were not even up to Dexron II let alone Dexron III.

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I heard back from Blackstone today on my ATF analysis. Apparently the news was so urgent that they even gave me a courtesy phone call! On the phone, they all but said that the Mobil 1 ATF is what's causing the problem...

(from printed analysis)

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DOUG: We didn't find any water in this sample, though we did find high insolubles and metals. The insolubles were gray, indicating they contained metals and were not just oxidation byproducts (which are black). Excessive heat can also cause high insolubles. The iron and copper probably show wear at the clutch plating, so you might want to start there as you figure out what's wrong with your transmission. You might also want to double check that Mobil 1 ATF is okay for use in this transmission. Not all oils are okay in all transmissions. We don't know about this particular one.


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Basically, copper was shown at twice the wear it should be (133ppm) and iron was more than 3x what it should be (291ppm) and after only a few thousand miles!

I brought some Diamond brand ATF with me on my way down to work this time, but I need a couple more quarts and a priest to completely exorcise the old fluid.

My plan is to home flush the A/T through the cooler line, drop and clean the pan, replace the filter, and replace all the ATF. Hopefully that will give better results. I'll follow it up in a few months with another analysis to confirm, but as a head start to those using Mobil 1 ATF without any kind of additive, DO NOT USE IT on your Montero/Raider A/T!

Hopefully, after my 20mo Mobil 1 ATF experiment, my A/T isn't too far gone that I can't save it with a simple fluid change. Glad I'm dilligent about maintenance and performance issues. I also plan on installing a larger A/T cooler at some time in the near future (despite the outcome of this experiment). Also want to add a temp sensor in the A/T oil pan just to monitor future occurances.

This makes me want to send in a sample of my rr diff gear oil. I've been finding a lot more metal shavings on the drain plug since switching to Mobil 1.

The good news is that there was no water found in the system, which means my gearbox breather system is performing well and that my A/T temp sensor is performing as it should. - Hey, you've got to find the positive in everything!

A/T info:
Mitsubishi KM148 (A44D)

--------------------
LOST ARK (IL)
'89 Raider 3.0L V6 (6G72) w/ KM148 (A44D) A/T
"The Millennium Falcon of automobiles"

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I am worried because I just put Mobil 1 ATF in my '95 Montero where the manual says "Dexron II" or equiv.

 

[unDummy]

So the Mobil1 ATF was doing some cleaning?
Sounds to me that someone wants to blame the fluid for their transmission neglect/abuse/lack of maintenance/improper ATF level/.......

Post or PM me the link. Love to read the entire thread.

 

[JohnBrowning]

I have used Mobil-1 ATF anyplace Dex I,II or III is called for and have never had a problem. I have used it in Toyota's and in Domestics with no fanfare at all. The over heat light alone tell's use it is not fluid issue. We also know that M1 ATF is fine for all DEX applications! So we either have a cleaning issues as was pointed out earlier or we have a mechanical problem that is not related to the fluid at all and the fact that the fluid was changed just prior to the start of the problem is just a coincidence!

 

[Ken2]

Older Hondas that used Dexron-II do best with either Honda's ATF or Dexron-III plus Lubegard HFM supplement. In this case, and maybe the Mistubishi, modern Dexron-III is not perfectly backward compatible.


Ken

 

[Winston]

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You might want to try the Diamond version.

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Are you saying to use Mitsubishi's Diamond SP III A/T fluid? I know that is what they recommend for all their transmissions now, but I thought the Mobil 1 should work fine since the manual says to use Dexron II.

quote:

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SPF can make that for you.

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I do not understand this statement.

 

[Doug Hillary]

Hi,
Winston - Dexron has been around for five decades or so in one form or another

In this country Castrol TQ-M-ST is recommended for some Misubishis. They say "...particularly for those equipped with damper clutches."

Misubishi went for a decade or so with "marginal" manual and auto transmissions.
A number of especially formulated lubricants were introduced to mask or alleviate some of the shortcomings. Some were successful - and some not

Mobil's ATF 220 here is Dexron 11D compliant

Regards
Doug

 

[Winston]

Here is the link to the original thread. The guy is very meticulous with his maintenance. I am just surprised that it could be Mobil 1.

Ken, that is an interesting comment. This whole A/T fluid issue is so confusing.

http://www.4x4wire.com/forums/showf...33545&page=0&view=collapsed&sb=5&o=14&fpart=1

 

[MolaKule]

You might want to try the Diamond version.

SPF can make that for you.

 

[FazerZ]

I read the whole topic on the 4x4wire board detailing the experience and I have serious doubts that the Mobil 1 ATF was the cause of his troubles. Even with diligent and regular service, sometimes a transmission will just take a slow dive to destruction.

It really sounds like he had some lockup convertor trouble or possible some poor cooler flow that has been causing him trouble.

The point being, the trouble was already existing, and the fluid has nothing to do with his complaints.

Even the oil analysis seems to point to possible clutch plate or thrust washer trouble. Both items in which any fluid should be able to work successfully against failure.

We have also used Mobil 1 ATF in a number of applications w/o any trouble.

The whole theory of the problem just seems odd and completely circumstantial so far.

Winston, Diamond ATF is a friction-modified fluid, that is necessary to give the correct shift feel, you could easily substitute Chrysler 7176, or ATF+3. I'm thinking this transmission should still be in the A40 series, so the effect on shift feel should be minimal.

Mobil 1 Syn ATF is not a match for Diamond ATF. It will not cause damage, but it could change the shift feel.

MolaKule meant SPF (specialty formulations) can provide you with the proper formulated ATF to meet the Diamond ATF specs.

DH

 

[Winston]

Fazor,

Thanks for your info. I agree that he is pretty quick to blame Mobil 1. This whole ATF fluid issue is driving me bonkers. My 95 mitsu manual calls for Diamond ATF or Dexron II. So I assumed Mobil 1 which is Dexron III (and Dexron II) would be OK. I think I will get an ATF analysis soon just to confirm that my A/T is OK with Mobil 1.