Trans question mabey wrong fluid

[tireroastin93XJ]

Ok, I called 3 different trans shops and they all said the same thing, use ATF+3 fluid in my 93 auto. All of them also said since it has 133,000 miles on it and hasn't been changed every 30,000 miles, not to change the fluid if it's running good, which it is. They said changing it could make it start slipping which I've heard from a lot of mechanics. They also said even if by some chance it has dexron lll in it, the one quart of atf+3 I put in it won't hurt anything. One of the shops rebuilt the trans in my 92 T-bird 3 yrs ago with a 3 yr/36,000 mile warranty on all his work and all he uses is Mobil 1 in everything, but that's on a freshly rebuilt trans. I was also told if I bought a re-man Chrysler trans and didn't use atf+3 or 4 that it would void the warranty. Talk about not knowing what to do!
Mike

 

[chadc]

what fluid to use? wouldn't you think thats a simple question . local jeep dealer says dexronIII, autozone says ATF3 dexron only for topping off, a local tranny shop says atf3, haynes says mercron atf ( i assume is dexron/mercron III) Well that sure clears things up.
chadc

 

[skipc]

Lotta EMOTIONAL opinion out there ;-)

I agree, very confusing. What might help is a discussion on the actual properties of DexronII and ATF+3, as well as DexronIII, and how meeting the Mercon spec adds to it, and the ATF+4 spec. Then a treatise on what the tranny needs...

The tranny is easy, relatively speaking. It has metal-to-metal contact that needs lubrication, friction pads that need to not slip (being composed of x material), and ports and passages that need a certain viscosity limit to allow proper flow (actually there's probably other fluid properties like shear strength, but all modern fluids should be good at all of them - a tranny is a tranny).

The tricky part is getting something that will allow 'grab' on the bands/pads and prevent friction everywhere else. Viscosity should all be about the same I'd guess. I've seen discussions on how one is 'grabbier' than another, but no real data (and maybe no real knowledge).

I do know that a big issue is how the bands/pads react with or work with the particular fluid. Of course, mixing them is another issue ;-) Some bands in some trans are composition. The fluid would be very critical to those since they could be dissolved, or could absorb fluid. That's why the mfg has a certain spec for fluid. I think I read the AW-4 has bronze friction surfaces (?). If so, it may not be critical... I also suspect that compatability with an application (ie DexronIII/Mercon can be used in all DexronII, III, and Mercon applications) doesn't mean it's better by definition, just compatible. It could be that, let's say, lubrication ability is reduced in Mercon for more grab (hypothetical). If the Dexron II spec says 0.4 or more (whatever units), and DexronII actually WAS 0.6, and DexronIII comes in at 0.5 (they needed less slip in the modern trannies) and Mercon needed even less, like 0.4, it would still meet the official DexronII spec, but would it be better than real DexronII??? It doesn't usually turn out that mixing things to make a product fit all makes it the best one for any particular application...

That doesn't, by itself, say ATF+3 is better. We don't have real numbers.

If someone could find/post relevant comparison specs (how is 'grabiness' spec'd?) we could see if perhaps DexronII was 0.8 units, ATF+3 0.9 units, and DexronIII 0.95 units of whatever. If we decide 0.8 is the best, then ATF+3 is closest today. If more is better, DexronIII is best....

It might also be possible that in moving to vIII, and adding Mercon compliance to it, a quality changed that makes it not the best choice too. So TODAY, ATF+3 is better. It's only a continuum on a scale of properties. DexronIII has properties that were demanded by manufacturers of later transmissions. While they might be 'suitable' for DexronII applications, it might not be the best fit if actual DexronII were around. Not saying that's the case, but it's a possibility. At least until someone comes up with a list of defining properties for each and we see. Then the discussion turns to which properties are important to the AW-4.

It'd be cool to decide it here first for the world ;-)

 

[chadc]

Talked with aamco, they use dexron, they also say do not mis dexron and atf3. The bands they use are brass, and the friction pads are a carbon material.
I found some spec sheets at pennzoil.com just because it was the first oneI found.

http://www.pzlqs.com/Tech/Pdsheet/D...DexronIIIMerconAutomaticTransmissionFluid.pdf

http://www.pzlqs.com/Tech/Pdsheet/DomesticMarketing/Gear&Transmission/pdf/ATF3.pdf

According to them atf3 is for Jeep and Chrysler vehicles, WITHOUT the aw4. They describe the dexron as a multifuntion fluid.
The specs don't really mean much to me :dunno: , I'm sure they do to some of you.
I get the impression dexron is the one, means I need to completely purge mine. Whats the best way to that, besides paying a shop to do it.
chadc

 

[ZmOz]

Just because YOU haven't heard about it doesn't mean it's ok. Yes, I have heard about mixing ATF+3 and Dextron many times. The result is allways a dead transmission. THEY ARE NOT COMPATIBLE!! Synthetic and regular oils are compatible and perfectly ok to mix.

Ok, I called 3 different trans shops and they all said the same thing, use ATF+3 fluid in my 93 auto. All of them also said since it has 133,000 miles on it and hasn't been changed every 30,000 miles, not to change the fluid if it's running good, which it is. They said changing it could make it start slipping which I've heard from a lot of mechanics.

The reason all these idiots say to use ATF+3 is because they think you have a Chrysler transmission. The AW4, thank god, is not a Chrysler transmission. It is made by Asin Warner and is DESIGNED TO USE DEXRON! Look in your manual. It will say Dexron II. Go look under your jeep at the drain plug on your transmission pan. It will have DII stamped into it. Dexron III is a direct replacement for II. ATF+3 is NOT a replacement.

I was also told if I bought a re-man Chrysler trans and didn't use atf+3 or 4 that it would void the warranty. Talk about not knowing what to do!

This is again beacuse the AW4 is not a Chrysler. They think it is.



For the love of god! Will somebody please explain to my why the hell anyone would use ATF+3? It cost more and is the wrong fluid. Whether or not it works is irrelivant. WHY would you buy a more expensive fluid that could very easily damage a $2000 transmission? Do any of you use gear oil in your engine? You might as well if you're going to use ATF+3 in your transmission...

 

[tireroastin93XJ]

The reason all these idiots say to use ATF+3 is because they think you have a Chrysler transmission. The AW4, thank god, is not a Chrysler transmission. It is made by Asin Warner and is DESIGNED TO USE DEXRON! Look in your manual. It will say Dexron II. Go look under your jeep at the drain plug on your transmission pan. It will have DII stamped into it. Dexron III is a direct replacement for II. ATF+3 is NOT a replacement.




This is again beacuse the AW4 is not a Chrysler. They think it is.



For the love of god! Will somebody please explain to my why the hell anyone would use ATF+3? It cost more and is the wrong fluid. Whether or not it works is irrelivant. WHY would you buy a more expensive fluid that could very easily damage a $2000 transmission? Do any of you use gear oil in your engine? You might as well if you're going to use ATF+3 in your transmission...

Well, that helps. I didn't know the aw4 wasn't a Chrysler trans. I assume that's what is in my 93? So assuming it has dexron ll in it, the trans shops said the one quart of atf+3 I put in won't hurt it. I would like to flush it but I'm afraid since my fluid wasn't changed on a regular basis, I'll fry the trans.
Mike

 

[ZmOz]

Well, that helps. I didn't know the aw4 wasn't a Chrysler trans. I assume that's what is in my 93? So assuming it has dexron ll in it, the trans shops said the one quart of atf+3 I put in won't hurt it. I would like to flush it but I'm afraid since my fluid wasn't changed on a regular basis, I'll fry the trans.
Mike

The AW4 was put into the XJ in 1987 and is basically unchanged since then. That would have been half way through 1986 for model years, that's before chrysler took over and before ATF+3 existed. An almost identical version of the AW4 is used in some Toyotas, which also use Dexron. Of course nobody would ever even think about using ATF+3 in one of those since it isn't a Chrysler. Unless you went 100k or so without changing the fluid, don't worry about changing it. Do it slowly, drain the pan and refil - that only changes half the fluid. Then do it again in a few thousand miles, you've only then changed 75% of the fluid. Do it a few more times after that....