Most might have already seen this, but take the time to read the facts about both fluidsn esp with viscosity. I currently use Dex-VI and this is basically why I use it http://www.sandyblogs.com/techlink/2009/05/dexron-vi.html
Dex-VI vs Dex-III..Nice Read; Facts on both fluids
- Thread starter NightRiderQ45
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GREAT ARTICLE!
Dex-VI =
Happily, I have experienced the vastly improved viscosity stability and friction modification in my '94 Buick. These attributes alone should have more folks loooking to convert their older vehicles over to Dex-VI.
Dex-VI =
Happily, I have experienced the vastly improved viscosity stability and friction modification in my '94 Buick. These attributes alone should have more folks loooking to convert their older vehicles over to Dex-VI.
Thanks for the congrats people. I have always been on the Dex-VI bandwagon after reading the posted link over a year ago but I couldn't remember the link. After I ran across it today, I HAD to post it because certain people beat Dex-VI up here on this site but really have nothing to prove their side other than "it came out think like water.." but the link states facts about both fluids ESPECIALLY the viscosity retention & the reason why DEX-VI starts low.
I'm actually going to do a drain & fill this weekend with 2qts of ST Dex-VI and two old 1qt bottles Coastal Dexron-III (licensed) and Nissan Matic-D I found in my father's garage (just so they won't go to waste).
I'm actually going to do a drain & fill this weekend with 2qts of ST Dex-VI and two old 1qt bottles Coastal Dexron-III (licensed) and Nissan Matic-D I found in my father's garage (just so they won't go to waste).
JHZR2
Staff member
Hadnt seen that, but it is pretty good. Im still on the fence wrt dex VI in my Dex II-specced Original 1981 and 1982 MB diesels.
Thanks!! This was the link that I ran across myself. Dex VI is just better period. Most cars I see at the junkyard have around 150-170k miles with the 4t60e/3800 combo. Dex III was probably in most transmissions. I'm at the upper end off the life expectancy with almost 171k miles. I have did mostly short trips 6-10 miles for at least the last 30k miles and 10-15 mile trips before that since I got the car at 108k. I want it to last to at least 200k miles and hope the Dex VI helps out.
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Originally Posted By: JHZR2
Hadnt seen that, but it is pretty good. Im still on the fence wrt dex VI in my Dex II-specced Original 1981 and 1982 MB diesels.
I would NOT use Dex VI in those old Benz 4-speed autos. GM may back spec Dex VI for all of THEIR transmissions that used older versions of Dexron, but those Benz transmissions are not modern GM designs. They are actually closer in design to GM's old fluid-coupled Hydramatic transmission which was introduced in 1939, nearly three decades before Dexron was introduced.
Hadnt seen that, but it is pretty good. Im still on the fence wrt dex VI in my Dex II-specced Original 1981 and 1982 MB diesels.
I would NOT use Dex VI in those old Benz 4-speed autos. GM may back spec Dex VI for all of THEIR transmissions that used older versions of Dexron, but those Benz transmissions are not modern GM designs. They are actually closer in design to GM's old fluid-coupled Hydramatic transmission which was introduced in 1939, nearly three decades before Dexron was introduced.
I think I might be one of those people who are lumped in the group of people who "beat Dex-VI up."
Let me state for the record my position on it: I think it's probably a perfectly fine ATF.
My only experience is with Supertech Dexron VI in a low mileage 4T65-E. It was not good. That particular ATF was prone to foaming, and driving downhill for a long distance could create conditions in that particular transaxle that would lead to substantial foaming of the fluid.
I have not tried (or tested--does anyone remember my test thread?) other brands of Dexron VI. But I do contend that Supertech Dexron VI in a 4T65-E has a good chance of being problematic unless you are a flatlander.
Since GM still sells cars with the 4T65-E and they come filled with Dexron VI, I strongly suspect that brands other than Supertech are OK. I really doubt that the GM of 2010 would sell cars with transaxles that malfunction when driving downhill.
Let me state for the record my position on it: I think it's probably a perfectly fine ATF.
My only experience is with Supertech Dexron VI in a low mileage 4T65-E. It was not good. That particular ATF was prone to foaming, and driving downhill for a long distance could create conditions in that particular transaxle that would lead to substantial foaming of the fluid.
I have not tried (or tested--does anyone remember my test thread?) other brands of Dexron VI. But I do contend that Supertech Dexron VI in a 4T65-E has a good chance of being problematic unless you are a flatlander.
Since GM still sells cars with the 4T65-E and they come filled with Dexron VI, I strongly suspect that brands other than Supertech are OK. I really doubt that the GM of 2010 would sell cars with transaxles that malfunction when driving downhill.
Dex VI is a great fluid. However, some people have had problems using it in Dex III and II applications. So it is sort of a trial and error thing sometimes with older applications. Sometimes it works fine, sometimes it causes problems with how the tranny shifts.
As a general rule, I only will use brand name tranny fluid (such as Toyota in T-IV or GM brand in Dex or Ford in type F) and the exact type called for. With a Dex III tranny (which I don't have right now) you'd have to go either GM Dex VI or a different company that claims to meet the Dex III specs since GM doesn't make it or license III any more.
As a general rule, I only will use brand name tranny fluid (such as Toyota in T-IV or GM brand in Dex or Ford in type F) and the exact type called for. With a Dex III tranny (which I don't have right now) you'd have to go either GM Dex VI or a different company that claims to meet the Dex III specs since GM doesn't make it or license III any more.
True, there is definitely some limitation with Dex-VI in older applications, but the "beat up" crowd I was speaking about is the crowd that states that Dex-VI viscosity is too low, but little do they know, Dex-VI stays in viscosity where Dex-VI starts high then drops lower than even Dex-VI specs.
dnewton3
Staff member
DEX VI is a great fluid, but it is NOT as backwards compatible as GM would have some people believe.
Allison specifically discourages its use prior to a seal material changeover, to address chemical issues with the seals versus the licensed chemisty of the add-pack of the fluid.
Allison specifically discourages its use prior to a seal material changeover, to address chemical issues with the seals versus the licensed chemisty of the add-pack of the fluid.
I think the ATF viscosity argument is silly in general. Between Dex/Merc and D-VI, we're talking about viscosity differences that amount to about 6°C to 12°C changes in operating temperature. Transmissions are designed to work well over a much wider range of temperatures than that.
I really suspect that either viscosity will work just fine in all transmissions, and that other performance characteristics (friction, oxidation, foaming, anti-wear, etc.) are really what matter.
I really suspect that either viscosity will work just fine in all transmissions, and that other performance characteristics (friction, oxidation, foaming, anti-wear, etc.) are really what matter.
very astute post.
Trans have a very careful modulation of pressures so a small swing in viscosity is unlikely to cause any change at all.
Trans have a very careful modulation of pressures so a small swing in viscosity is unlikely to cause any change at all.
JHZR2
Staff member
Originally Posted By: G-MAN
Originally Posted By: JHZR2
Hadnt seen that, but it is pretty good. Im still on the fence wrt dex VI in my Dex II-specced Original 1981 and 1982 MB diesels.
I would NOT use Dex VI in those old Benz 4-speed autos. GM may back spec Dex VI for all of THEIR transmissions that used older versions of Dexron, but those Benz transmissions are not modern GM designs. They are actually closer in design to GM's old fluid-coupled Hydramatic transmission which was introduced in 1939, nearly three decades before Dexron was introduced.
Interesting. Folks who own cars like mine over at peachparts are slowly starting to transition over. No issues yet. My thinking is along the lines of what you mention.
However, there is no real dex II fluid besides redline, which Im not sure if I want to be using in a 30yo AT (not because of it being in bad shape at all, rather more along the lines of materials issues), and the D/M fluids will become more and more questionable regarding quality as time goes by.
Maybe castrol transynd or the equivalents is the best bet?!?
Originally Posted By: JHZR2
Hadnt seen that, but it is pretty good. Im still on the fence wrt dex VI in my Dex II-specced Original 1981 and 1982 MB diesels.
I would NOT use Dex VI in those old Benz 4-speed autos. GM may back spec Dex VI for all of THEIR transmissions that used older versions of Dexron, but those Benz transmissions are not modern GM designs. They are actually closer in design to GM's old fluid-coupled Hydramatic transmission which was introduced in 1939, nearly three decades before Dexron was introduced.
Interesting. Folks who own cars like mine over at peachparts are slowly starting to transition over. No issues yet. My thinking is along the lines of what you mention.
However, there is no real dex II fluid besides redline, which Im not sure if I want to be using in a 30yo AT (not because of it being in bad shape at all, rather more along the lines of materials issues), and the D/M fluids will become more and more questionable regarding quality as time goes by.
Maybe castrol transynd or the equivalents is the best bet?!?
Originally Posted By: JHZR2
Originally Posted By: G-MAN
Originally Posted By: JHZR2
Hadnt seen that, but it is pretty good. Im still on the fence wrt dex VI in my Dex II-specced Original 1981 and 1982 MB diesels.
I would NOT use Dex VI in those old Benz 4-speed autos. GM may back spec Dex VI for all of THEIR transmissions that used older versions of Dexron, but those Benz transmissions are not modern GM designs. They are actually closer in design to GM's old fluid-coupled Hydramatic transmission which was introduced in 1939, nearly three decades before Dexron was introduced.
Interesting. Folks who own cars like mine over at peachparts are slowly starting to transition over. No issues yet. My thinking is along the lines of what you mention.
However, there is no real dex II fluid besides redline, which Im not sure if I want to be using in a 30yo AT (not because of it being in bad shape at all, rather more along the lines of materials issues), and the D/M fluids will become more and more questionable regarding quality as time goes by.
Maybe castrol transynd or the equivalents is the best bet?!?
If I still had my 77 240D I would use a name brand, multi-vehicle ATF that is recommended for Dex III. These first generation fluid-coupled Benz transmission were designed when Type A fluid was the norm so I don't think they are too particular about fluid. The only reason I may be uncomfortable using Dex VI is because of its low viscosity. But if enough reports come in over time from people using it in these trannys without issue I will probably change my opinion. It would be interesting to see what Mercedes has to say about using Dex VI in these older models.
Originally Posted By: G-MAN
Originally Posted By: JHZR2
Hadnt seen that, but it is pretty good. Im still on the fence wrt dex VI in my Dex II-specced Original 1981 and 1982 MB diesels.
I would NOT use Dex VI in those old Benz 4-speed autos. GM may back spec Dex VI for all of THEIR transmissions that used older versions of Dexron, but those Benz transmissions are not modern GM designs. They are actually closer in design to GM's old fluid-coupled Hydramatic transmission which was introduced in 1939, nearly three decades before Dexron was introduced.
Interesting. Folks who own cars like mine over at peachparts are slowly starting to transition over. No issues yet. My thinking is along the lines of what you mention.
However, there is no real dex II fluid besides redline, which Im not sure if I want to be using in a 30yo AT (not because of it being in bad shape at all, rather more along the lines of materials issues), and the D/M fluids will become more and more questionable regarding quality as time goes by.
Maybe castrol transynd or the equivalents is the best bet?!?
If I still had my 77 240D I would use a name brand, multi-vehicle ATF that is recommended for Dex III. These first generation fluid-coupled Benz transmission were designed when Type A fluid was the norm so I don't think they are too particular about fluid. The only reason I may be uncomfortable using Dex VI is because of its low viscosity. But if enough reports come in over time from people using it in these trannys without issue I will probably change my opinion. It would be interesting to see what Mercedes has to say about using Dex VI in these older models.
Originally Posted By: Stu_Rock
I think I might be one of those people who are lumped in the group of people who "beat Dex-VI up."
Let me state for the record my position on it: I think it's probably a perfectly fine ATF.
My only experience is with Supertech Dexron VI in a low mileage 4T65-E. It was not good. That particular ATF was prone to foaming, and driving downhill for a long distance could create conditions in that particular transaxle that would lead to substantial foaming of the fluid.
I have not tried (or tested--does anyone remember my test thread?) other brands of Dexron VI. But I do contend that Supertech Dexron VI in a 4T65-E has a good chance of being problematic unless you are a flatlander.
Since GM still sells cars with the 4T65-E and they come filled with Dexron VI, I strongly suspect that brands other than Supertech are OK. I really doubt that the GM of 2010 would sell cars with transaxles that malfunction when driving downhill.
X2! I completely agree with your sentiments. Probably I'm lumped into that category of Dex-VI "bashers" because it didn't work well in my particular application.
It's fine fluid, just not for everybody's individual (older) application.
I think I might be one of those people who are lumped in the group of people who "beat Dex-VI up."
Let me state for the record my position on it: I think it's probably a perfectly fine ATF.
My only experience is with Supertech Dexron VI in a low mileage 4T65-E. It was not good. That particular ATF was prone to foaming, and driving downhill for a long distance could create conditions in that particular transaxle that would lead to substantial foaming of the fluid.
I have not tried (or tested--does anyone remember my test thread?) other brands of Dexron VI. But I do contend that Supertech Dexron VI in a 4T65-E has a good chance of being problematic unless you are a flatlander.
Since GM still sells cars with the 4T65-E and they come filled with Dexron VI, I strongly suspect that brands other than Supertech are OK. I really doubt that the GM of 2010 would sell cars with transaxles that malfunction when driving downhill.
X2! I completely agree with your sentiments. Probably I'm lumped into that category of Dex-VI "bashers" because it didn't work well in my particular application.
It's fine fluid, just not for everybody's individual (older) application.
I've heard both good and bad, so I'm still on the fence myself whether I should use it or not.
Granted, If I do it, it would be the full syn Valvoline Dex VI, on my low milage GM 4 speed...
Kinda makes me wonder if I do..if I would notice a difference between the Full and regular (syn blend) Dex VI...
Granted, If I do it, it would be the full syn Valvoline Dex VI, on my low milage GM 4 speed...
Kinda makes me wonder if I do..if I would notice a difference between the Full and regular (syn blend) Dex VI...
Probably you'd not see the negative results I and several others have seen with the syn-blend Dex-VI.
Just anecdotally, it "appears" that those of us who used the syn-blend (mainly SuperTech) Dex-VI have had problems, while others who use full synthetic Dex-VI aren't reporting problems (or as many problems).
Just anecdotally, it "appears" that those of us who used the syn-blend (mainly SuperTech) Dex-VI have had problems, while others who use full synthetic Dex-VI aren't reporting problems (or as many problems).
Maybe WhiteWolf or somebody more knowledgeable than me can chime in here, but it's my understanding that ONE reason GM came out with DexVI was to address shudder problems with some of their newer transmissions... which implies to me that the friction properties of DexVI are at least somewhat different than DexIII.
And even though DexVI has been been declared backwards-compatible... it's still a fact that lots of older transmissions were not designed for this particular fluid. It may be 'close enough', but it simply isn't the same ATF as, say, DexIIIG.
So it should come as no surprise that at some older transmissions don't 'like' DexVI. The 4T65E in my '01 Lumina does NOT work well with DexVI- it made the full-throttle 1-2 shift do a sickening slip & grab thing. I kept the DexVI in there for maybe 25k miles and just avoided full-throttle 1-2 shifts, thinking that maybe the trans. was on its way out. Then just as an experiment, I did a full flush with TranSynd (which claims DexIIIG on the jug- which is what this vehicle originally required). I let the wife drive it for maybe a week before I tried to full-throttle 1-2 shift... to let the clutches soak in the new fluid. And it shifts MUCH better. The full-throttle 1-2 shift is still softer than I'd prefer, but it's perfectly normal. No more slip & grab.
The 4T60E in my '94 Corsica, on the other hand, shifted perfectly with DexVI. Over the years, I ran supertech Dex III, then Penzoil Dex VI, then Transynd in that transmission... and never felt ANY difference in shift quality regardless of what fluid was in there.
So while I don't think there's anything 'wrong' with DexVI, and I would definitely use it in a vehicle that specifies that fluid... it may not be ideal for some older transmissions that were designed for DexIII. And it'll work fine in others... possibly most of them.
And even though DexVI has been been declared backwards-compatible... it's still a fact that lots of older transmissions were not designed for this particular fluid. It may be 'close enough', but it simply isn't the same ATF as, say, DexIIIG.
So it should come as no surprise that at some older transmissions don't 'like' DexVI. The 4T65E in my '01 Lumina does NOT work well with DexVI- it made the full-throttle 1-2 shift do a sickening slip & grab thing. I kept the DexVI in there for maybe 25k miles and just avoided full-throttle 1-2 shifts, thinking that maybe the trans. was on its way out. Then just as an experiment, I did a full flush with TranSynd (which claims DexIIIG on the jug- which is what this vehicle originally required). I let the wife drive it for maybe a week before I tried to full-throttle 1-2 shift... to let the clutches soak in the new fluid. And it shifts MUCH better. The full-throttle 1-2 shift is still softer than I'd prefer, but it's perfectly normal. No more slip & grab.
The 4T60E in my '94 Corsica, on the other hand, shifted perfectly with DexVI. Over the years, I ran supertech Dex III, then Penzoil Dex VI, then Transynd in that transmission... and never felt ANY difference in shift quality regardless of what fluid was in there.
So while I don't think there's anything 'wrong' with DexVI, and I would definitely use it in a vehicle that specifies that fluid... it may not be ideal for some older transmissions that were designed for DexIII. And it'll work fine in others... possibly most of them.
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