Atf+4 vs Dexron vi

Status
Not open for further replies.
P

pjc360

Joined
Nov 1, 2011
Messages
260
Location
montana
I've got a non lock up A-518 chrysler transmission in my 91 dodge power ram truck. The transmission was re-built in October of 2011 and it came with a 2 year warranty, the transmission has 5500 miles on it right now, I only use the truck for hunting and sometimes go for a little drives here and there. The builder told me he put dexron III in it, and he told me that's what he recomends to run in it.
So i followed his advice and ran the dex III he put in it since he was giving me the two year warranty, the warranty has been expired since October of 2013. I have been wanting to get rid of the dexron III and run a synthetic in it.
Which one would you run it between +4 and dex vi? Chrysler recomends +4, but factory fill on my transmission was dex III, and dex vi is supposed to be back words compatible.
My fiancée has a 2005 Volvo XC90 t6 that I am running dexron vi in right now, so it would be nice to stock one fluid for both vehicles. I haven't heard of too many people running dexron vi in a chrysler transmission. But since mine is all hydraulically controlled and a non lock up unit and was originally speced for dexron III, I figured th dex vi would be just fine in it. Even though it's a little thinner, the dex vi holds its viscosity a lot better then dex III and probly even a little better then +4. I have an auxiliary cooler and the factory cooler both hooked up and working. I just ant a synthetic for peace of mind, and longer service intervals, and of course better hot and cold protection. Which one would you run of the two?
 
Last edited:
Both are great fluids, ATF +4 would probably give you the edge during Winter though.
 
ATF+4 and Dexron/Mercon are very different specs. They have very different coefficients of friction for different amounts of clutch slip. I imagine the older RWD transmissions have a larger tolerance for using different fluids; i know that using any dex/merc in a FWD ATF+4 applications causes shudder, but that's electronically controlled transmissions with lockup.

Knowing your transmission specified DexronIII from the factory, then Dexron VI is the correct fluid.
 
I'm sure redline and amsoil are superior fluids, but I want to run something that's readily available to me in case I need a quart or two in a hurry.
From what I've read the +4 was developed to help with torque converter lock up chatter, which I don't have. So it basically comes down to which fluid is going to perform better? Which fluid will hold its viscosity better, which fluid will protect better in hot and cold climate.
Cost isn't really a factor as I can get both of them for around 5-6 bucks a quart, from what I've read dex vi performs basically the same as dex III when it comes to shift qaulity,. And it would be nice to stock one fluid in the shop for both of my vehicles, that's why I'm leaning towords the dex vi. I just thought I'd get people's opinion on the subject and see if there was something that would make +4 worth running over the dex vi. i don't want to run dex III because Its outdated fluid that's not even being certified anymore, gm isn't watching what people are calling dex III anymore, which means you could be buying something that's a lot less qaulity then the original dex III spec, which wouldn't suprise me at all with the big oil company's being as money hungry as they are.
 
Last edited:
Ever hear the saying if it ain't broke don't fix it? If it runs good leave it alone.
I gave my friend my old Dodge ram 250 with the 318 and i always used atf 3 when it was new and then atf4 after it was rebuilt in 2005 (my brother owned a transmission shop so it did not cost me anything)

After about 60,000 miles a trans line rotted and he lost fluid and burned the transmission so he had it rebuilt again by the guy that bought my brothers trans shop (this time it cost him $700.00 and he said the rebuilder used dex 3 this time. My brother used what the trans called for from the factory.
 
In my business we only rebuild engines stock and we tell almost everyone use what the oil cap or manual says. If the engine is a pre 1980's some rules may be changed.
 
Originally Posted By: pjc360


My fiancée has a 2005 Volvo XC90 t6 that I am running dexron vi in right now, so it would be nice to stock one fluid for both vehicles.


Certainly understand the logic but do you really have a stock of tranny fluid? You change it that often?
 
Originally Posted By: asand1
Maxlife is closer to Dex III than IV is, and its full synthetic. Cheap too.
maxlife is thinner than dex vi.
 
Originally Posted By: AZjeff
Originally Posted By: pjc360


My fiancée has a 2005 Volvo XC90 t6 that I am running dexron vi in right now, so it would be nice to stock one fluid for both vehicles.


Certainly understand the logic but do you really have a stock of tranny fluid? You change it that often?


yes I will be changing the fluid quite frequently in fiqncee's Volvo XC90 t6, it has a twin turbo'd engine and the transmission is a gm 4t65e and its. Ot even the he version. We have had it for 3 months and we've put 4000 miles on it and I've dropped the pan twice and re-filled with dex vi, I'm going to wait another 10 thousand miles before dropping the pan on the volvo again. I've been told keeping fresh qaulity fluid in that transmission is what's going to give it the best chance at succeeding. Those transmissions are well known for thier issues behind that t6 engine.
As for my truck with the chrysler A-518, I'll progly change the fluid in it every 15-20 thousand miles.
Most of the miles that will be put on the A-518 will be in the mountains where it's constantly working. Climbing hills, coming down hills, lots of stop and go driving in 4wd.
I've considered maxlife as well, but I don't think I need a high mileage fluid in my fresh re-built transmission, and it's also thinner then dex vi as someone has already mentioned.
I think I will go ahead and try dex vi in my A-518, if I notice the fluid causing the transmission to shift poorly then I will swap it back to dex III and leave it alone. I just like the idea of running a synthetic fluid in a transmission that I will be working pretty hard. Not to mention my engine has quite a bit of power and that also causes the transmission to work harder.
 
Split the difference and run one of the syn universals that is supposed to cover both Dex and ATF+4. Normally, I don't like the idea of a universal for an ATF+4 app, but in your case, it should work fine.
 
Many torqueflite builders (A727, A518, A618, etc) used to tell you to run the cheaper Dex III fluid because it is a "stickier" fluid which grabs the clutches differently than a full synth like ATF+4 will. The downside to this is, the DEX will wear out quicker and lose visc much faster than ATF+4. In the 20 hour KRL shear test, DEX III suffered a 40% viscosity loss compared to ATF+4. The builder of my 47RE initially recommended DEX for my trans when he built it for the above reason and price but those were the only reasons for his recommendation. ATF+4 is a superior fluid in every way to DEXIII. Ive been using ATF+4 @30k mile intervals for the past 100k miles and my trans has very little clutch wear when I drop the pan and the bands need minimal adjustments. ATF+4 is technically a 100k mile fluid but I change mine out more frequently due to my modified engine and the fact that it gets used to tow heavy loads.

As for using Dex VI its interesting to note the difference in viscosity. Viscosity plays an important role in TC performance and its stall characteristics.

ATF+4 cST@40C 33.24 cST@100C 7.51
DEXIII cST@40C 34.70 cST@100C 7.70
DEXVI cST@40C 29.50 cST@100C 5.83

The way I see it, you've got two valid options as you mentioned. Either DEXVI or ATF+4. DEXIII would be out of the picture if it were my transmission. ATF+4 is friction modified for the electronic control programs TCM. ATF+4 lets the TCC operate in patial lock up mode which other fluids are not capable of without slippage or shudder. None of this applies to you, however I feel ATF+4 with its group III base and patented shear stable VI improver make it a superior fluid. Just my opinion.
 
I run tractor fluid in my w250. If you want more torque capacity raise the line pressure. tractor fluid is about 10.5 at 100c. There is a 1/8 npt port on case passenger side to read line pressure. Pulling the kick down back will give more line pressure as well. The tractor fluid will help that non lockup converter transfer power better. I have pump turned up with 5x16 injectors no slipping, trans has 240k on it. Don't run more than 100psi without upgrading front band strut you will bend it. Then no 2nd gear. I just put a cast 5 inch deep pan on mine it lowered temp a good 10 deg. If your gonna run red fluid atf4 does not shear as bad.
 
91 RAM? Are you sure Chrysler/Dodge recommends ATF+4?

+4 is basically a Mercedes-spec trans fluid and was introduced during the MB/Chrysler years around 2000 or so. My 96 RAM spec's ATF+3 in the manual, which is a substantially different lubricant.

If your rebuilder suggests Dextron 3, I'd follow his advice, although jrmason's post is interesting. You definitely don't *have to* run ATF+4 in a '91; that fluid didn't exist when your truck rolled off the assembly line. Check your manual (or download one).
 
Last edited:
Use ATF+4. Its far superior than cheap DexronIII. It will also protect your transmission better. Builders are clueless when it comes to fluid.

ATF+3 and ATF+4 are the same addition package. +4 uses select base oils, usually Group III synth. +3 use a cheaper non synth base oil.

If you are stuck on Dex3, at least use a full synth or TES295 fluid.
 
Status
Not open for further replies.

Similar threads

S
Dexron VI
Replies
5
Views
749
Invisible
S
Mobil 1 Blue Label vs Dexron VI
Replies
9
Views
2K
tig1
B
Idemitsu Toyota Fluid Compatibility
Replies
4
Views
991
bbhero
L
ATF fluid a340 dex merc 3
Replies
16
Views
762
kschachn
G
Motomaster Low Viscosity ATF - Dexron 3 Application?
Replies
4
Views
556
Snagglefoot
Back
Top