AW4 Fluid ATF+4 >>> Dex III

[heyhar]

I think auxiliary tranny coolers should be mandatory. They extend the life of the fluid unbelievably. If Dex lV is indeed thinner, I'd stay away from it. It may offer too much slip in the torque converter, especially if a lot of driving is done at speeds lower than the speed at which the TC locks up.

 

[joe_peters]

Well, IMHO, if the transmission is worn out then definitely stick with the Dex III as any synthetic is just going to be more expensive and might make things worse.

That said, as the life of Dex III is only 30k miles, and that life gets halved for every 20 degrees of overheat, I would vote for the synthetics in a good transmission in any XJ that tows or sees much off road use.

Which synthetic to use is the question: Dex VI; ATF+4; one of the "universals"?

 

[Jeepguy03]

Well, IMHO, if the transmission is worn out then definitely stick with the Dex III as any synthetic is just going to be more expensive and might make things worse.

That said, as the life of Dex III is only 30k miles, and that life gets halved for every 20 degrees of overheat, I would vote for the synthetics in a good transmission in any XJ that tows or sees much off road use.

Which synthetic to use is the question: Dex VI; ATF+4; one of the "universals"?

My XJ has 105k miles. I am pretty anal about changing the fluids, the previous owner never changed them except for the oil (maybe). I plan on just running the Dex III and changing it often. As for a cooler, anyone have a specific one they like? I do have a hitch but I don't currently tow. I have a 2" lift waiting to go on, but will stay with 30" tires.

 

[87manche]

My XJ has 105k miles. I am pretty anal about changing the fluids, the previous owner never changed them except for the oil (maybe). I plan on just running the Dex III and changing it often. As for a cooler, anyone have a specific one they like? I do have a hitch but I don't currently tow. I have a 2" lift waiting to go on, but will stay with 30" tires.

The largest you can reasonably fit.

Stacked plate > Tube and fin

Run it straight from the trans line to the aux cooler, then plumb the aux cooler back into the oil/water cooler in the radiator. This will make sure that your aux cooler is doing most of the work, but also keep the ATF at the proper tempreature in cold weather.

 

[dukie564]

Dexron VI is the new version and is backwards compatible with Dexron III (discontinued). It has better heat reducing characteristics than DexIII and is synthetic. Both of these things are good things for your transmission.

ATF+4 is essentially the same thing as Dexron VI for the AW4 (although not compatible in new GM trannys that call for DexVI).

Either will do fine - recommend Dexron VI for cost savings sake (slightly cheaper than ATF+4).

 

[87manche]

Dexron VI is the new version and is backwards compatible with Dexron III (discontinued). It has better heat reducing characteristics than DexIII and is synthetic. Both of these things are good things for your transmission.

ATF+4 is essentially the same thing as Dexron VI for the AW4 (although not compatible in new GM trannys that call for DexVI).

Either will do fine - recommend Dexron VI for cost savings sake (slightly cheaper than ATF+4).

just because GM says it's backwards compatible does not make it so. Everything using Dex III is out of warranty so they don't really care.

I asked the technician at the dealership, he told me it was noticeably thinner and that it was engineered for gas mileage. Sure, it has better heat characteristics, it stands up to higher temps because it operates at higher temps. That may be fine for newer transmissions designed to operate at those temperatures, but it probably isn't for the AW4.

Stick with what toyota said to put in it.

 

[dukie564]

just because GM says it's backwards compatible does not make it so. Everything using Dex III is out of warranty so they don't really care.

I asked the technician at the dealership, he told me it was noticeably thinner and that it was engineered for gas mileage. Sure, it has better heat characteristics, it stands up to higher temps because it operates at higher temps. That may be fine for newer transmissions designed to operate at those temperatures, but it probably isn't for the AW4.

Stick with what toyota said to put in it.

I'm guessing you copied that from a TOYOTA forum? Thinner isn't an issue. Jeep has updated their recommendations to Dexron VI from Dexron III for a reason.

Dexron VI fluid is far superior to basic former DEX III fluids because it has approximately twice the viscosity retention, and oxidation resistance, as the former fluid it replaces. It is “thinner” in nature, but it stays in grade much better and longer than traditional DEX III fluids

 

[87manche]

No, I don't go to any toyota forums, but they are the people that made the transmission, and last I knew they still said to put Dexron II/III in it.

not to mention that we're dealing with transmissions that likely have 100K+ miles on them, and since you'll never really get all of the old fluid out is it good to mix them?

Jeep updated the recommendation so that the dealers don't have to keep 12 different fluids on hand, Just like they did with ATF+4 when it came out. Again, these are all out of warranty, so what does ChryCo care if Dex VI hoses your transmission in 20K miles after it was serviced?

Anyway, I don't even own an AW4 anymore, so I really don't care, but I would stick with III, and I did, and I never had a problem with it, even in an 87 that had 330K miles on the odometer when I sold it.

 

[kastein]

Aisin Warner actually made the transmission. Toyota (and if you check wikipedia, about 4 million other companies) just used it.

Mixing fluid is way too overhyped. It doesn't really matter, mixed is better than old but not as good as all new.

I doubt they did it to kill old transmissions, from what I read they changed their recommendation after years of tests to verify the ATF+4 and other fluids would not kill them. Testing a new fluid takes time.

 

[DieselSJ]

The prev owner of my '91 kept most of her service receipts. I went back through them and it looks like she had the trans serviced about every 30-40k miles at the dealer. Every receipt listed +4 as the ATF they used. It has 221K miles on it. I don't think using +4 is going to kill the trans.

 

[birchlakeXJ]

I don't think atf+4 will kill the transmission, but I frequent 4 XJ forums and have run into a few people who have experienced some "slippage" symptoms when they switched to atf+4.

This symptom went away when they went back to Dex/Merc.

And the weird thing is that some AW4s do okay with atf+4, but a few seem to not care for it. It makes it hard to quantify. May be the additive package.

But for that reason that "some" have trouble with it, I'm sticking with Dex/Merc III compatible.

This is one of those back and forth issues that will continue until the end of time, which is fine. Get everybody's opinion and make your own decision......

 

[Spunkmeyer]

All I know is that the dealers were told to only use DEX/MERC III in an AW-4 until after the 7/70 warranty ran out on the Jeep Cherokee. That says something to me.

 

[DieselSJ]

Here is an interesting read -

http://www.allpar.com/mopar/transmissions/fluids.html

Note the viscosity losses from shearing.

 

[rwdawg2]

I've run this http://www.autozone.com/autozone/ac...m&fromString=search&itemIdentifier=597210_0_0_
In the trans for a couple of minutes to clean out everything then use the cooler lines to drain (as someone on this thread has already mentioned) while someone else fills the trans with new fluid (via dipstick). Shut her down once the fluid turns red.

Works like a charm and never worried about leaks like I've had to when I drop the pan.

Just my two cents. Thanks for the info on what trans fluid to use with these trannies.

-Lindsey