TheSamba.com :: View topic - Dexron III vs VI ATF in Automatic Transmissions (revisited)

Sun Mar 16, 2014 11:29 am

[Moderator note: It is Dexron, not Dextron!]

There are a few threads here talking about using Dextron VI, which is the current formulation of Dextron, in place of earlier formulations. Volkswagen originally called for Dextron or Dextron II, neither of which has been available for a long time as far as I know. Dextron III has been the go-to fluid for some time. Anyway, as far as I have read, everyone seems to think III and VI are fully compatible.

I did a bit of research and found some internet gold which may or may not apply to our vehicles: There is a fellow who is a former Allison fluids engineer who is quite generous with his time on a number of forums. I have gone partway through one of his threads and found something interesting. Apparently Dextron VI is NOT fully compatible with Dextron III. In Allison transmissions, Dextron VI hardens seals:

Quote:
DEXRON-VI would be incompatible with Viton seals used by Allison Transmission in MY 2004 products. Tests showed that the additives used in DEXRON-VI hardened the older (non-DEXRON-VI compatible) Viton seals. This could lead to cracking and leakage at some point .... hard to determine when though. Could be thousands of hours depending mostly on temperature.

This is from
http://www.irv2.com/forums/f125/former-allison-transmission-fluids-engineer-89293-3.html

Obviously I don't know if this applies to our transmissions and I also don't know the seal materials in our transmissions.

So here's my question: Does anyone have long term experience using Dextron VI in their automatic transmission? Any change in the transmission's performance? Any leaks?

Sun Mar 16, 2014 11:52 am

I have run all sorts of ATF fluids in my automatic. Dex, Type-F, High-Visc, and now this "Royal Purple Automatic Trans Fluid", which sounds, "generic" and also says on the label, "isn't compatible with Dex", but I have always flushed the transmission before adding different fluid types. My auto has never driven so well. I can't tell that it shifts at all.. very smooth.

TerryK suggests Type-F and I can vouch that it did solve a slow shifting problem I had last winter.. but really, like Oils, you are probably fine to use whatever suits your driving conditions.

Just my 2c.

Sun Mar 16, 2014 11:56 am

I'm a big fan of Castrol Transmax High Mileage in our old slush-boxes.

Sun Mar 16, 2014 12:07 pm

I just read the spec sheet for Castrol Transmax and it goes in pretty much anything!

Quote:
Acura ATF-Z1 (except in CVTs)
Chrysler ATF+3®, ATF+2®, ATF+®
Ford MERCON®
General Motors DEXRON®- III
H, II-D, II, DEXRON®; 9986195; Type A, Suffix A (TASA)
Honda ATF-Z1, ATF DW-1 (except in CVTs)
Hyundai SP-II, SP-III
Infiniti Matic-D,
Matic-J, Matic-K
Lexus Type T, T-III, T-IV
Nissan Matic-D, Matic-J, Matic-K
Toyota Type T, T-III, T-IV
Volvo All Specifications

Sun Mar 16, 2014 12:18 pm

I'd probably accept whatever GTA recommends as gospel.

Sun Mar 16, 2014 1:35 pm

ThankYouJerry wrote: I'd probably accept whatever GTA recommends as gospel.

What do they recommend?

Sun Mar 16, 2014 2:14 pm

Yeah, what's a GTA?

Sun Mar 16, 2014 2:26 pm

table wrote: Yeah, what's a GTA?

http://www.germantransaxle.com/

Wed Mar 19, 2014 10:07 pm

I called german transaxle today to see what their opinion was. They had three things to say:

1) Dextron VI is okay, but the tranny might leak a bit because it's thinner than III.

B) Do NOT use Valvoline.

iii) Synthetic ATF is a good thing to use.

Wed Mar 19, 2014 10:13 pm

Here is a quote from Kateka at GTA regarding the rebuilt auto trans I just bought from them last week:

"In regards to which fluids. You will use a full synthetic ATF in the auto section and you will use a 75/90 GL5 full synthetic in the final."

I will use Redline brand.

Thu Mar 20, 2014 10:10 am

table wrote: There are a few threads here talking about using Dextron VI, which is the current formulation of Dextron, in place of earlier formulations. Volkswagen originally called for Dextron or Dextron II, neither of which has been available for a long time as far as I know. Dextron III has been the go-to fluid for some time. Anyway, as far as I have read, everyone seems to think III and VI are fully compatible.

I did a bit of research and found some internet gold which may or may not apply to our vehicles: There is a fellow who is a former Allison fluids engineer who is quite generous with his time on a number of forums. I have gone partway through one of his threads and found something interesting. Apparently Dextron VI is NOT fully compatible with Dextron III. In Allison transmissions, Dextron VI hardens seals:

Quote: .fluid…
DEXRON-VI would be incompatible with Viton seals used by Allison Transmission in MY 2004 products. Tests showed that the additives used in DEXRON-VI hardened the older (non-DEXRON-VI compatible) Viton seals. This could lead to cracking and leakage at some point .... hard to determine when though. Could be thousands of hours depending mostly on temperature.

This is from
http://www.irv2.com/forums/f125/former-allison-transmission-fluids-engineer-89293-3.html

Obviously I don't know if this applies to our transmissions and I also don't know the seal materials in our transmissions.

So here's my question: Does anyone have long term experience using Dextron VI in their automatic transmission? Any change in the transmission's performance? Any leaks? Have you considered asking the original manufacture of dex VI who creates and designs the upgrades..if you have any leaks now, fix it…DexVI is more temp stable, less shearing..in other words, most people who drive around still thinking that the dex3 is better don't realize that this oil has sheared to a number far less then dexVI will ever reach..anyway, here is a very basic intro for your reading @ http://www.gmls4.com/index.php?topic=604.0 …

Thu Mar 20, 2014 2:48 pm

spacecadet wrote: ...but I have always flushed the transmission before adding different fluid types.

How exactly do you do this? I'm looking at having to do some transmission work and while the fluid is drained I was going to try Type-F (shift from D to R seems to confuse my tranny for a good few seconds and shifting in general isn't buttery). I wasn't sure how to go about flushing the old Dex out of the tranny and TC to move on to a different fluid.

Also should I consider running something like Seafoam Trans Tune for a while before I do the work and change the fluid just to scrub the gunk out? Should I consider put some in with the new fluid too?

Sorry to Hijack!
Thanks,
GT

Thu Mar 20, 2014 5:47 pm

geo_tonz wrote: spacecadet wrote: ...but I have always flushed the transmission before adding different fluid types.

How exactly do you do this? I'm looking at having to do some transmission work and while the fluid is drained I was going to try Type-F (shift from D to R seems to confuse my tranny for a good few seconds and shifting in general isn't buttery). I wasn't sure how to go about flushing the old Dex out of the tranny and TC to move on to a different fluid.

Also should I consider running something like Seafoam Trans Tune for a while before I do the work and change the fluid just to scrub the gunk out? Should I consider put some in with the new fluid too?

Sorry to Hijack!
Thanks,
GT

I'm not a big fan of transmission flushes..you really don't want all the debris and swarf that is laying around harmlessly in your automatic to get stirred around.

To get most of the old ATF out requires three/four changes of ATF in the transmission pan. The old ATF (about 3 quarts remains in the transmission) hangs out in the torque converter and elsewhere.

Remove the filler pipe and remove the pan..remove the old screen filter hiding under the cover on the valve body..install a new filter, clean the inside of the pan and put it back together. Just snug up the filler pipe connection but be sure your pan gasket is seated and not leaking.

Refill with your favorite ATF to the correct level..warm and at idle on the dipstick. Stop the engine. Go back under the Vanagon and loosen the filler pipe on the pan and dump the ATF..don't remove the pan. Change the favorite AFT and refill again (rinse and repeat) do this a few times and you have changed the AFT and done your own "flush". Have about twelve quarts of your favorite AFT handy to do the service.

Fri Mar 21, 2014 10:49 am

Thanks!

I do like the idea of using something to dissolve varnish in the tranny like the seafoam prior to draining to try to clean up sticky valves, etc. but I can envision it loosening junk that then cycles around the transmission. If it's more trouble than it's worth I guess I'll just skip it.

What is it that you like about the Castrol Transmax High Mileage? In your opinion a better product than Type F for this application?

Fri Mar 21, 2014 2:12 pm

geo_tonz wrote: Thanks!

I do like the idea of using something to dissolve varnish in the tranny like the seafoam prior to draining to try to clean up sticky valves, etc. but I can envision it loosening junk that then cycles around the transmission. If it's more trouble than it's worth I guess I'll just skip it.

What is it that you like about the Castrol Transmax High Mileage? In your opinion a better product than Type F for this application?

I used the Castrol in my old 88 VW Vanagon...it had a very bad leak from the servo piston seal "O" ring (leaking on the outside of the case)

Changed the fluid over to the Castrol and the leak stopped..I was surprised.

I rebuilt that automatic and the servo "O" ring was showing its age and very brittle/hard. The Castrol did a good job.

I use the Castrol now in my newly rebuilt (3 years ago) 010 in my 91 Vanagon with the Audi turbo internals...Shifts fine and the Castrol is very serviceable in our older 010 automatics.

Fri Mar 21, 2014 6:46 pm

AtlasShrugged wrote: I used the Castrol in my old 88 VW Vanagon...it had a very bad leak from the servo piston seal "O" ring (leaking on the outside of the case)
The second gear brake band piston? This is exactly my issue. I have the gasket set and am working up to an in-van repair of it and am concerned I might be facing table's problem:
http://www.thesamba.com/vw/forum/viewtopic.php?t=587711&highlight=automatic+transmission

Very tempting to see if just the Castrol fixes my leak, but I do want to road trip with this van so I should probably tear into it and see if there's something more serious wrong.

Fri Mar 21, 2014 8:27 pm

Geo..do a fluid change (only once) without changing the filter and pan gasket with the Castrol HM ATF ..clean the transmission with some "GUNK" spray then drive it a while and see if you have the same luck I did with the servo housing leak.

Table's problem in the link is he has a failed servo "C" clip..any fluid change won't help that..he need a new piston and housing..the best being the later style VW piston/servo or a piston/servo and housing off an Audi 200 turbo.

When I rebuilt my 88 automatic, most of the "O" rings, metal clad piston seals and other seals were due to be changed. The Castrol bought me some time on the visible external and invisible internal leaks. Transmission always shifted fine..22 years is long enough for most seals and gaskets.

If you do go into your transmission, do find an Audi turbo 010 transmission in the bone yard and pirate parts off of that..the Vanagon 010 is darn near bullet-proof when the heavy duty turbo parts are used.

Fri Mar 21, 2014 8:39 pm

Nothing on the planet short of soaking them o-rings in brake fluid will revive them--make them pliable and soft again.

While the Castrol HM fluid might be OK--it ain't the Wizard of Oz ,and will not restore rock hard o-rings.

Don't dream any farther than this message on that one.

Change the o-rings, swap filter's, and drop some Ford Type F in the trans.
Better yet--Drop some B&M Hydro Trick Shift in the trans.

They both are a miracle in a better shifting automatic trans--neither are a cure all for worn out and stiff rubber seals or o-rings.

Fri Mar 21, 2014 9:31 pm

AtlasShrugged wrote: Table's problem in the link is he has a failed servo "C" clip..any fluid change won't help that..he need a new piston and housing..the best being the later style VW piston/servo or a piston/servo and housing off an Audi 200 turbo.

Yes, but he found the mess investigating a leak from this cover, as I am, and it sounds like the circlip fail is common, with this leak being a possible symptom of the internal fail? On his the inner seal was destroyed by the clip and probably lead to the leak of the outer seal, which I am suspicious about with mine now. Any performance give-aways of this fail on the tranny? What ends up happening to the tranny? Catastrophic failure? Mine seems to shift ok, if not buttery smooth.

I hate to agree with Terry but I'm thinking I better open it up and make sure everything's kosher before I take the kiddies and wife on a longer road trip, and pop the new seals on I already bought. If I was just puttering around town I would consider buying extra time with the Castrol, but with loaded coastal highway driving in mind I want a more durable, permanent fix. I can't seem to find it online in Canada either, so maybe it's just a US thing (though we do have the Castrol High mileage oil...I've used it and liked it as my van seemed to as well). I'll look for it when I get out of camp.

Still on the fence about Castrol vs Type F though.
Thanks for all the off-topic-but kida related help!

Sat Mar 22, 2014 12:51 am

geo_tonz wrote:

Yes, but he found the mess investigating a leak from this cover, as I am, and it sounds like the circlip fail is common, with this leak being a possible symptom of the internal fail? On his the inner seal was destroyed by the clip and probably lead to the leak of the outer seal, which I am suspicious about with mine now. Any performance give-aways of this fail on the tranny? What ends up happening to the tranny? Catastrophic failure? Mine seems to shift ok, if not buttery smooth.

I am starting to think I may have caused the damage to the piston and cylinder during the removal process. Here's what I suggest: Before you start to remove the snap ring that holds the brake band piston cover in place, clean the surface carefully of all the grime you can with a screwdriver and/or solvent and/or other scraping tool. I didn't do that and the cover got hung up on the case when I pulled out the snap ring. Then I had to force it out and I wasn't very graceful in that process. I found in my junkyard work that with a screwdriver I could carefully pry the cover off bit by bit, aided by the springs behind the cover. On the van, I hammered on it and did all sorts of stupid stuff which may have caused the damage. The broken circlip should be able to bounce around in there quite happilly for some time, provided the fluid passages are on the sides so the circlip just falls to the bottom of the cylinder. (take-home message: Orient the fluid passages on the sides, not top and bottom when reinstalling)

In any case, my o-rings and sealing rings were rock hard so need to be changed.

I guess all this should be in the other thread huh?