Transmission Fluid

[Paul S]

I purchased a gallon jug of Valvoline "Max Life" Multi-Vehicle ATF for a reasonable price at Walmart.

I got it home and read that it is a full synthetic. The label says it is good for GM, Ford, Toyota and Honda. It also claims it is a replacement for Dexron II, III, & VI.

I haven't heard of a synthetic ATF and was wondering if you folks had any concerns or thoughts on the subject.

[winterset]

I am getting ready to change out my 18 year old Dexron iii with Dexron vi. I purchased quarts at Walmart for 4.27 each. Its Walmart brand and GM certified. I would be reluctant to mix anything else in there. I understand Dexron vi is what GM recommends to be put in all Cadillacs. I will do a radiator cooling line drain followed by a pan drop, new GM filters, cleanout of pan, and a new GM gasket.

[Cadillac Jim]

The Valvoline web site says that Maxlife ATF conforms to Dexron VI specifications. Dexron VI is the recommended fill for the 4T80E used in your 1999 Seville.

Whether it is better or worse that other ATF products certified to conform to GM Dexron VI specifications I can't say. Whether the additives specific or unique to Valvoline Maxlife ATF will help or not, I can't say.

I will say that if you service your transmission every 50,000 miles or so and do not abuse it or tow with it, and you repair any issues that throw an OBD code promptly, you should have virtually unlimited life out of your transmission, other than possibly replacing shift solenoids and maintenance items like gaskets and filters, and of course ATF.

Dexron VI provides 230% the clutch life of Dexron III and has virtually no viscosity change over normal transmission temperatures. If you flush with Dexron VI, you *will* notice better shifts when the transmission is cold, as with the first shift in the morning. And you will more than double the remaining life of the clutches.

Also, I agree with what winterset says.

[KHE]

The Valvoline web site says that Maxlife ATF conforms to Dexron VI specifications. Dexron VI is the recommended fill for the 4T80E used in your 1999 Seville.

Whether it is better or worse that other ATF products certified to conform to GM Dexron VI specifications I can't say. Whether the additives specific or unique to Valvoline Maxlife ATF will help or not, I can't say.

I will say that if you service your transmission every 50,000 miles or so and do not abuse it or tow with it, and you repair any issues that throw an OBD code promptly, you should have virtually unlimited life out of your transmission, other than possibly replacing shift solenoids and maintenance items like gaskets and filters, and of course ATF.

Dexron VI provides 230% the clutch life of Dexron III and has virtually no viscosity change over normal transmission temperatures. If you flush with Dexron VI, you *will* notice better shifts when the transmission is cold, as with the first shift in the morning. And you will more than double the remaining life of the clutches.

Also, I agree with what winterset says.

I am hesitant to buy into the the 230% longer clutch life, etc. with Dex 6. It was introduced in 2005 for the 2006 model year vehicles and GM does not want to have two types of fluid where there is a chance someone would put Dex-3 in a trans spec'd for Dex 6. Since the fluid is always backwards compatible, the easiest thing to do is to specify that Dex 6 is recommended. The big difference is Dex-6 is all synthetic. You would have no issues using Dex-3 in your 1999 transmission - thet is what irt was designed to use.

That said, if you have a supply of Dex-3 on the shelf, there is no reason not to use it - I asked the transmission shop that evaluated my trans in my '97 STS when it was generating debris and he told me, "That's what it was designed to use - no problem in using it."

[Cadillac Jim]

Actually, the 230% of clutch life means 130% longer clutch life. That means that if you have, say, 130,000 miles on your 4T80E and it has perhaps 50% of its clutch life remaining, and you do a flush with Dexron VI, the expected clutch life will then be at least that of a new transmission with a Dexron III fill.

I had my 4T80E flushed with Dexron VI at a Cadillac dealer and noticed far better shifts in the transmission, particularly when cold. The Northstar PCM trains itself on transmission clutch performance so that the shift performance remains as the transmission is designed as the clutches wear. But the viscosity of Dexron III varies significantly over the temperature range of the transmission. Since most "training" data is for a hot transmission, cold shifts will be harder, particularly the first shift in the morning, even if you let the car idle for a few seconds so that the HO2 sensors come online and the DFI goes closed loop.

But, yes, the 4T80E prior to the 2006 model year were designed for Dexron III and, in fact, hot Dexron III is almost identical in most hydrodynamic properties to Dexron VI. The 4T80E will perform as designed, as long as designed, with Dexron III.

The dealer and owner's manual will tell you never to service a 4T80E unless it is overheated; this may be good advice if you agree on 100,000 to 150,000 miles as an acceptable transmission life. By servicing the transmission occasionally, say every 50,000 miles, you can perhaps double its life, and this is continuing to use Dexron III to flush or top off the transmission as part of servicing, no Dexron VI required.

[Z15]

I would not use WM brand, its low priced fluid from unknown vendors.

Just because something is GM certified does not mean its a good product. Ask all those with Cobalt's and defective ignition switches.

When it comes to GM certified in reality all they care about is getting their piece of the pie, pay to play with GM.

For Paul S.

AMSOIL came out with a 100% synthetic ATF back in 1980. Its in my CTS4 and in my Denali.

[Paul S]

Thank you all for your comments. I truly appreciate it and value your oppinions.

[joeb]

If your 15yr old car has never had a trans overhaul, than I would stick with dex 3 if u can find it. If it has been recently rebuilt, ? It might work better with dex6. But what did the shop put in when they rebuilt it recently? Sort of a sideways comment. The number of members here with 94-97 cars is getting thin. Most 99 cars have motor issues, not trans issues.

[rockfangd]

The only issue I have run into with the 96-99 tranny related is the torque convertor.

My 96 has a bad torque convertor. Hard to tell if the light werent on all the time. Even with the torque convertor problem it is still going strong

[Cadillac Jim]

To summarize:

• There is nothing wrong with Dexron III in a transmission that was designed for it. You will get the design life out of the transmission with design performance. If there is a warranty (repair, exchange transmission) then Dexron III will satisfy anyone's requirements for service without voiding their warranty on a 4T80E sold prior to the 2006 model year.
• Dexron VI offers more consistent shifting with temperature and longer remaining life. You will have to flush with it, not just top off after a service, to get noticeable improvements in cold shifting. It's more expensive than Dexron III.
• The Dexron label means that GM certifies the transmission fluid to meet their specifications for service for transmissions that recommend that fluid (Dexron III or, for 2006 and later models, Dexron VI). Different vendors may have better quality fluid but if it has the GM license for Dexron, it meets GM requirements for servicing, e.g. using it will not void a GM warranty. We have one member who does not trust WM for quality, probably because the price doesn't seem to reflect what Dexron VI promises to be; it's your decision where you get Dexron.

If you have a P0741 but no other code for electrical performance of the TCC solenoid, you likely need a new torque converter. One member here let his go for years and the TCC eventually shed enough debris to bring down the whole transmission, so you should plan to get it fixed, but you can take your time and make your plans to your personal satisfaction without urgent pressure.

[rockfangd]

very true. Mine started about 2 years ago, that was the first time it ever threw the code anyway. Now it is on all the time. Still driven daily though. I dont plan on fixing it though.

[Göran W]

About DEXRON III. As I understand Wikipedia there is NO DEXRON III...... All approvel from GM expiered in 2006 and any "out there" is leftovers or just fake. It may well fill the old data but it is not approved by GM.

[KHE]

GM is not licensing Dex-3 anymore but that doesn't mean the product that is out there does not meet the requirements of Dex-3. GM has "manual transmission fluid" that IS Dex-3.

I specifically asked the local transmission shop about Dex-3 when I replaced my trans. on my STS in December and he told me to use Dex-3 - he uses it in 2005 and older cars and has not had a comeback.

[Z15]

[Cadillac Jim]

With automatic transmission for which Dexron VI is recommended for use as fill or replacement, you have a choice. You can use the less expensive Dexron III and get the performance and life designed and built into the 4T80E, which no one has ever complained about; it's a magnificent transmission and is pretty much bulletproof. I've never heard of one giving problems at under 100,000 miles even when never serviced.

With Dexron VI, you get the uniformity of viscosity over temperature that we see in synthetic oils, which, with the shift performance monitoring, memory, and tuning of the PCM with the 4T80E, will provide perfect shifts. The 230% clutch life of Dexron VI over Dexron III will proved 130% of the clutch life remaining after you do a full flush.

[MAC]

I just replaced my trans fluid and filter a couple of months ago. Took at least 2 hours because it was the first time and it is a pain to refill with 9 quarts. I used mostly Dex VI. The pan had no gasket at all. The filter came with a rubber gasket but I threw it out, figuring I would just bolt the pan back on the way it came off. And sure enough no leak.

[KHE]

No pan gasket??? Was there an o-ring in a groove? What keeps it from leaking?

[MAC]

No pan gasket??? Was there an o-ring in a groove? What keeps it from leaking?

The pan has a slight raise line of metal that apparently prevents leaking. Other than that, I don't know. If there was a gasket at one time, it wasn't there when I dropped it, and no doubt the pan would have leaked if it had a gasket, which was falling apart. I have yet to see a drop of trans fluid on the ground even though there isn't a gasket.

[winterset]

What brand did you use? You have 250k on this car - Was there and debree, or just that very thin layer of grey sediment coating the bottom of the pan?

[MAC]

What brand did you use? You have 250k on this car - Was there and debree, or just that very thin layer of grey sediment coating the bottom of the pan?

I refilled with 5 quarts of Walmart's Super Tech Dexron VI, 2 quarts of Super Tech Dexron III, and 2 quarts of Super Tech High Mileage fluid--all compatible with GM vehicles. My initial thought was that I was going to do two fluid changes because I figured I would only get about 5 quarts max out of the pan. But when I unscrewed the drain plug the fluid poured out about 9 quarts. The second change would be with high quality brand name fluid and maybe an addative. As far as sediment, I was quite surprised that there was only a thin layer of gray sediment on and near the magnet in left rear corner of the pan. I used paper towels to wipe the pan clean.

[Cadillac Jim]

The ridge on the oil pan is there to force a tight seal with the gasket. A gasket should come with a transmission service kit. If you don't use a kit, you should get a gasket the next time you pull the pan.

[KHE]

According to the AD Delco website, there is a pan gasket for the 2005 STS transmission pan. It is part no. 96042862.

It's nice that there is a drain plug on the transmission pan.

[winterset]

What brand did you use? You have 250k on this car - Was there and debree, or just that very thin layer of grey sediment coating the bottom of the pan?

I refilled with 5 quarts of Walmart's Super Tech Dexron VI, 2 quarts of Super Tech Dexron III, and 2 quarts of Super Tech High Mileage fluid--all compatible with GM vehicles. My initial thought was that I was going to do two fluid changes because I figured I would only get about 5 quarts max out of the pan. But when I unscrewed the drain plug the fluid poured out about 9 quarts. The second change would be with high quality brand name fluid and maybe an addative. As far as sediment, I was quite surprised that there was only a thin layer of gray sediment on and near the magnet in left rear corner of the pan. I used paper towels to wipe the pan clean.

I would not use an additative in your transmission fluid. I think upgrading to Dexron vi is enough of an upgrade for your clutches. No telling what any other fluids can do or even counteract the benefits of the upgraded vi fluid.

Imo, those additatives are for the people who never changed their fluid, and want a cheap way out of feeling good that they are maintaining their car.

[Cadillac Jim]

Dexron VI offers 230% the clutch wear of Dexron III and viscosity that varies very, very little over transmission operating temperatues. But from experience you don't get the benefits in shifting unless you flush the transmission and have essentially 100% Dexron VI in it.