Dexron III and a lot of it

[Paul S]

I have past the 100,000 mile mark on my '99 STS and was thinking about the transmission maintenance. I looked up in the owners manual what was recommended for it and it tells me it is Dexron III and the required amount to fill the transmission is 15 quarts.

Is it possible this is a misprint on the quantity of ATF needed for a change? Also with Dexron III not being on the local auto parts shelves any more, is there a substitute that I can use?

[Cadillac Jim]

Dexron VI is backward compatible in nearly all GM and other transmissions that originally used Dexron III, including the 4T80E versions prior to 2006. Dexron VI has two main advantages over Dexron III, which you can still get if you really want it. One advantage of using Dexron VI is very consistent viscosity from cold to hot working conditions, which means that the PCM will learn the shifting really well and your transmission will have a perfect shift every time, from the first cold start until you park the car. The second is probably more important to you, the clutches and bands will last 130% longer than with Dexron III, which means that if your transmission has, say, half its band and clutch life left, the life after switching to Dexron VI will be greater than the expected transmission life when the car was new.

I had my 4T80E serviced every 30,000 to 40,000 miles until I sold it early this year and never noticed a difference until I went to a GM dealer and asked for a 100% flush with Dexron VI. A couple of days later, the perfect shifts with a cold transmission got my attention and I have been totally for switching to Dexron VI when you have your transmission serviced. Simply draining the transmission, cleaning the pan, filter and pickup, and filling to spec will change only about half the fluid and you won't feel a difference in the shifts. I don't know about the extended band and clutch life with mixed Dexron III and Dexron VI but the 4T80E is known as pretty much bulletproof (except possibly for the shift solenoids) as long as you don't tow or abuse your transmission with the Dexron III fill.

Cost is higher for Dexron VI than for Dexron III, and flushing is expensive because more fluid is used than the transmission holds. Contrary to what you may hear elsewhere, used fluid is not pumped into transmissions by the flushing machines used at GM dealers, so you won't get debris pumped into your transmission by having it flushed at a GM dealer. Most GM dealers use the flushing machine when you have your transmission serviced there and have for about ten years; you need to either insist on a conventional service or go to a transmission mechanic to get a traditional service.

If you really want a conventional service but would like the better shifts and transmission life of Dexron III, you can do like I did: get a conventional service, then wait a few months to make sure that everything that has been disturbed but not removed has settled, then get your transmission flushed with Dexron VI.

To answer your question, some manual transmissions and gearboxes that used Dexron III still do so, and GM has re-named the product for these applications. I don't recall the product name to ask for but someone will step in and provide that.

[KHE]

15 quarts sounds like the overhaul quantity, not the drain and refill amount.

[winterset]

What about that technique of running the fluid out of the radiator cooling lines? - I have never don it, but I heard it's a good way of getting out most of the "old" fluid.

[KHE]

What about that technique of running the fluid out of the radiator cooling lines? - I have never don it, but I heard it's a good way of getting out most of the "old" fluid.

If that technique was used, then the amount will be near the 15 quarts.

[Paul S]

KHE

If the 15 quarts is the overhaul qantity, what would be your guess on the drain and refill amount?

[KHE]

KHE

If the 15 quarts is the overhaul qantity, what would be your guess on the drain and refill amount?

Not sure offhand maybe 8 quarts. It should state the amount in the specifications section of the owner's manual.

[JimD]

When the 4T80E is "drained" by disconnecting the cooler return line at the radiator end tank, you will be replacing 11 to 12 quarts of fluid.

And I would use Dexron VI.

[winterset]

I intentionally never shop or buy at Wal-Mart, but last year for my GM minivan, I dropped the pan, replaced the filter & gasket, and put in Dexron VI. I recall it was tricky finding GM approved Dexron VI, and the Wal-Mart brand was "GM certified". I had to buy 12 quarts. Make sure you dont put in one of those universal fluids.

[Cadillac Jim]

I wouldn't dodge WalMart because they carry low-end lines as well as other merchandise. So long as the product is properly branded and licensed, as your Dexron VI is, great. And, they sell distilled water at 50 cents a gallon jug (the last time I looked, about a year ago), and they will have plenty on hand to fill all your cars if you are doing anti-freeze for three or four cars, not just a gallon or two like many small stores.

[joeb]

What's the difference between Walmart dex6 and dealer dex6?

[JohnnyG]

What's the difference between Walmart dex6 and dealer dex6?

About $6.00.

(Sorry, I know it's an old joke . )

[Cadillac Jim]

If it's got the Dexron VI logo on it, it's licensed by GM and certified to meet GM specifications.

[Z15]

Dexron is like Dexos, a marketing scheme to bilk the oil companies out of money on the pretense of protecting the consumer. Whether you call it paying "protection" like the wise guys do, or "oem certified" like the car industry does, it's still paying "them" to be on their certified list under the veiled threat of "warranty denial.

Rebranders

• Total Lubricants USA, Inc (License Number J-60370
• Uni-Select Inc. (License Number J-60371)
• O'Reilly Auto Parts (License Number J-60372)
• Delta Petroleum Co. Group (License Number J-60373)
• Tier One Brands (License Number J-60374)
• Repsol/YPF S.A./YPF Brazil (License Number J-60375)
• AutoZone Parts, Inc (License Numbers J-60376 & J-60378)
• Alliance Parts Warehouse (License Number J-60377)
• Old World Industries (License Numbers J-60379 & J-60380)
• The Pep Boys (License Number J-60381)
• Yinhang Petrochemical Co. (License Number J-60382)
• National Pronto Association (License Number J-60383)
• Genuine Parts Company (License Number J-60384)
• TPI Oil Company, Ltd. (License Number J-60385)
• Automotive Distribution Network (License Number J-60386)
• Omni Specialties Packaging (License Number J-60387) <------WM source for lubes
• Aftermarket Auto Parts Alliance, Inc. (License Number J-60388)
• Besybuy Distributors (License Number J-60389)
• Uni-Select Eastern, Inc (License Number J-60390)

[Texas Jim]

Dexron is like Dexos, a marketing scheme to bilk the oil companies out of money on the pretense of protecting the consumer. Whether you call it paying "protection" like the wise guys do, or "oem certified" like the car industry does, it's still paying "them" to be on their certified list under the veiled threat of "warranty denial.

Rebranders

• Total Lubricants USA, Inc (License Number J-60370
• Uni-Select Inc. (License Number J-60371)
• O'Reilly Auto Parts (License Number J-60372)
• Delta Petroleum Co. Group (License Number J-60373)
• Tier One Brands (License Number J-60374)
• Repsol/YPF S.A./YPF Brazil (License Number J-60375)
• AutoZone Parts, Inc (License Numbers J-60376 & J-60378)
• Alliance Parts Warehouse (License Number J-60377)
• Old World Industries (License Numbers J-60379 & J-60380)
• The Pep Boys (License Number J-60381)
• Yinhang Petrochemical Co. (License Number J-60382)
• National Pronto Association (License Number J-60383)
• Genuine Parts Company (License Number J-60384)
• TPI Oil Company, Ltd. (License Number J-60385)
• Automotive Distribution Network (License Number J-60386)
• Omni Specialties Packaging (License Number J-60387) <------WM source for lubes
• Aftermarket Auto Parts Alliance, Inc. (License Number J-60388)
• Besybuy Distributors (License Number J-60389)
• Uni-Select Eastern, Inc (License Number J-60390)

And your point is ?????

Are you saying to buy transmission fluid that is NOT marked DEXRON???

[winterset]

I understand the points, but as a consumer it's important for me to know that the fluid I am putting in my car is certified by the company that built the car to begin with. If the oil company has to pay a little fee to GM for them to verify the formulation, I'm willing to pay a few extra dollars for that validation. From what I recall, the walmart brand dexron VI was about $4.00. the GM brand was about $8.00

My car is 17 years old, and I am still careful about using the right fluid, as one stupid mistake can cost me more than the car is worth. I would imagine that someone with $40k invested in their car would care even more about using the correct fluids.

I was explaining this to my son the other day about shops using these universal fluids, and how doing the job yourself is a guaranteed way that you are using the right stuff. In fact I went to Autozone last night and picked up a gallon of GM certified prestone dexcool and spent $16 for a full concentrate bottle. the other non GM prestone coolant was $13 - so for $3.00 more, I felt at ease.

We don't expect the certified fluids to cost the same or less than these universal fluids do we? - IMO, I don't think its a scheme at all, but a necessity.

[JohnnyG]

I agree with Winterset here, but I look at it a little differently. I feel Dexos is sort of a scheme, since many oils probably meet the requirements but do not choose to pay GM's licensing fee. Top Tier gas falls into that same category. So I choose to use Dexos certified oils in my DTS, but don't concern myself one bit with Top Tier gasoline. I know the differences in gasoline, and believe me, it ain't much.

Dexron, on the other hand is more than just a licensing scheme. It is a specifically formulated product for which there is no substitute. In other words, I don't feel you can go out and put Ford ATF into a GM trans and expect it to survive or operate properly. I'm not just talking about temperature extremes or smooth operation here, I'm talking about actual mechanical failure due to the use of the wrong fluid.

All of that said, if a rebrander such as WalMart sells Super Tech brand Dexron VI, you can bet it will work in a GM trans.

[Z15]

Which is more expensive, paying more for a better product up front, or paying for a repair that may have been avoided by using the expensive product?

I understand that using licensed products is fairly safe, however just because it's licensed does not mean it's a good product; it only means it is good enough to meet some standard and no more. There may be better products on the market, there are certainly excellent products that are not GM licensed fluids that will outperform the licensed products.

[JohnnyG]

there are certainly excellent products that are not GM licensed fluids that will outperform the licensed products.

That depends on how you define "outperform" and "better". Take motor oils for example. Amsoil and Royal Purple do not choose to be certified by GM and in some cases by API. Their performance is excellent in most applications, with good wear numbers due to their generally higher ZDP levels or other additives. Unfortunately those higher levels of ZDP in a stock vehicle equipped with a catalytic converter and driven to the design max of GM's 300,000 mile point, can poison the cat and render it ineffective. When GM certified products are used, things like that are considered.

[Z15]

In case of AMSOIL, they have 2 oils (XL and OE) that are API SN spec's and are API certified (not GM licensed) so there no chance of poisoned cats. AMSOIL even puts it on the label that it not only meets dexos1 spec's, it exceeds them. They would be foolish to put it on the label if they could back it up. The FTC would stop them in an instance but they never have because its true.

The label is advertising and truth in advertising requires anything put on the has to be true.

Under the Federal Trade Commission Act:

• Advertising must be truthful and non-deceptive;
• Advertisers must have evidence to back up their claims; and
• Advertisements cannot be unfair.

[JohnnyG]

I said that in some cases their products choose not to be API certified for the reasons that I stated, such as their racing oils. I also know that Amsoil markets more than two oils. However, that was just an example of what the Dexos certification MIGHT mean, pretty much in simplified terms.

My point is that GM does a LOT of engineering and testing of their vehicles in order to certify the performance, longevity, and cost per mile to the end customer. These engineers know their stuff, and the certification process comes at great cost to GM. There is no point in trying to "reverse engineer" any of those efforts. So if they deem it necessary to have a licensing program or a certification in order to meet those requirements, I'm going to do my best to adhere to them.

[Z15]

Fyi - Here's evidence GM is doing it for money..............and the only reason they have gone to licensing (selling the rights to the logo) is because no one followed them yet.

[JohnnyG]

I don't believe that GM has gone to licensing OR selling the rights to the logo in order to make more money. I simply feel that they do it to ensure that any aftermarket products comply with the requirements of their validation process. If this were an effort to make money, they sure didn't charge enough. The bankruptcy alone should be proof enough of that.

This 2009 article points out that it was an idea and it was never adopted. You can't buy Chevy oil or Caddy oil, but you can buy Toyota oil and BMW oil, etc. We are talking about something different here, especially as it applies to Dexron. It may be the "next best thing" as far as the stealerships are concerned, but so far it has had no impact on the Quick Lube industry or the DIY market.

[JimD]

....I simply feel that they do it to ensure that any aftermarket products comply with the requirements of their validation process.

Exactly.

In the case of GM, the Dexron standard has been the recommended transmission fluid for as long as I can remember. Likewise Mercon for FOMOCO transmissions. Where is the conspiracy?

This 2009 article points out that it was an idea and it was never adopted. You can't buy Chevy oil or Caddy oil, but you can buy Toyota oil and BMW oil, etc.

My 2011 GM vehicle Owner's Manual 'recommends' dexos specification engine oil.

The next paragraph in the manual provides an escape clause like this "In the event that dexos approved engine oil is not available at an oil change or for maintaining proper oil level, you may use a substitute engine oil displaying the API Starburst symbol and of SAE 5W-30 viscosity grade....

GM maintains a web page listing brands that meet the dexos specification.

http://www.gmdexos.com/licensedbrands/dexos1licensedbrands.html

[Cadillac Jim]

It doesn't follow that a spec for GM engines would drive people to the dealer, unless that oil is available only for oil changes at the dealership, which would cause consumer revolt: lost sales. In places I get oil changes in out-of-warranty cars, I notify the shop of which oil I want and how much (if they have to ask) and give them a couple of days to get it in before I bring in the car.