Thread: Royal purple max or GM dex 3

If someone could explain why royal purple is any better, then maybe it would be worth the crazy cost of it.

So just stick with dexron 3, it's cheap and does the job required. Replace like half a quart of fluid with lucas and call it good. You'll need nearly 8 quarts with a pan drop.

What about Dex VI?

Dexron 3 is cheaper and his year car does not call for Dexron 6. Could you run the newer stuff sure, but it's not helping anything.

I go buy cost and the fact that cars up 2005.5 all used the older dexron 3. Last time I looked dexron 3 was $4-5 per quart and 6 was $8 a quart. Buying in bulk likely saves some money or getting a gallon jug. This was the valvoline line too.

Originally Posted by Fivefingerdeathpunch

If someone could explain why royal purple is any better, then maybe it would be worth the crazy cost of it.

Because window sticker HP?

Dexron VI...its backwards compatible and considered by GM to be superior to Dex 3 AND costs very little more than Dex 3. Walmart Supertec Dexron VI is about $4 per quart. I have been using Dexron VI for the last 100,000 miles in my original 4T65E tranny and it now has 180,000 miles on it working perfectly.

Sure it's backwards compatible and is considered better by GM now but it does the job no differently than Dexron 3. Anything that that fluid has to offer does the transmission no favors, it's not going to know the difference.

My comments are based on cost, it's still a cheaper fluid and exactly why I'd used it.

I read somewhere (not sure now true it is) that because GM no longer "owns" the DEXIII name or whatever, there is no longer a DEXIII "standard."

So because of that, you can have differing standards from different manufacturers, on what is supposed to be the same fluid.

Again... not sure how valid that argument is.

Dexron-VI[edit]

The fluid specification for Dexron-VI was introduced in 2005, and was first used as the GM factory-fill automatic transmission fluid for model year 2006. All Dexron-III licenses expired permanently at the end of 2006, and GM now supports only Dexron-VI fluids for use in their automatic transmissions,^[3] although fluids asserted by their manufacturers to meet Dexron-III standards continue to be sold under names such as Dex/Merc. These fluids are not regulated or endorsed by GM.^[4]
Dexron VI is of a slightly lower viscosity when new compared to the prior Dexron fluids (a maximum of 6.4 cSt at 100°C for Dexron VI and 7.5 cSt for Dexron III), but the allowed viscosity loss from shearing of the ATF during use is lower for Dexron VI, resulting in the same lowest allowed final viscosity for both Dexron III and VI (5.5 cSt).^[5] The lower viscosity is intended to gain improvements in fuel economy by lessening parasitic drag in the transmission. Since Dexron VI is not allowed to thin out (lower its viscosity) as much as Dexron III during use, it requires the use of higher-quality, more shear-stable (less prone to thinning while in use) base oils.^[4] The current GM specification that defines the fluid is GMW16444, which superseded the original specification, GMN10060.

Really what?

The blurb about dexron 6 means nothing. Prove that it does anything more for the transmission, no way is anyone ever going to notice a fuel mileage increase when switching fluids. Besides the final viscosity when warm/running temp I assume is of the same. Both fluids can carry the same change intervals, both will work the same and besides these transmission fail all the time and fluid is normally not the factor. It's design flaws and or power breaking stuff.

It's not worth beating a dead horse about.

I can read and understand that they are a different fluid with SLIGHTY different vsicosity ratings and the fact that GM no longer uses that fluid because they went with a more synthetic blend fluid to go with the times.

Just because GM says its the superior fluid (only superior because it's the newest design) does not make it any better than the old stuff. Prove that it does the job any better, prove that it being a synthetic type fluid that it's making a difference in a vehicle like ours.

Newer vehicles with more complex transmissions would gain from the synthetic fluid, atleast thats what they want you to believe.


My whole point from the start is that is does not matter what you run, nothing else that you could use will do the job any different. Neither dexron 6 or royal purple will reduce wear, gain you MPG, make it last longer or any of that. The cheapest crap on the market is all thats needed from the start, switching brands or fluid is completely a choice the owner can make. All it will do is make your wallet lighter in the end.