: 4T80E vs Dexron VI, GM new standard

02-03-06, 05:34 PM
So apparently the new ATF fluid is out: Dexron VI.

I believe I read somewhere (don't ask me where--I did a search on Google) that GM made it backwards compatible, and recommends it.

Dexron VI apparently is much more stable and resistant.

A year ago, when I purchased the ETC, I had the transmission fluid drained, and the filters changed (no, the shop did not own a flush machine, and did not believe in them). I suppose they did what they were paid to do.

However, I drained a quart or so of fluid and it doesn't look bright red like new fluid.

A buddy mechanic of mine is willing to help me exchange the fluid via the transmission pump--hook it to a bucket and pour new fluid until it comes out bright red.

I am wondering if I should consider Dexron VI. It is factory fill for 2006 GM trannies, including the North*.

02-04-06, 11:23 PM
The main thing with the trans fluid is to smell it. It it smells oily then it is likely fine. The slight darkening of the fluid is not really a concern. If the fluid is burnt it is very recognizable with the acrid/burnt smell. Unmistakeable.

If you do want to replace it go with the latest Dextron fluid. The specs are backwards compatible for all the transmissions. The later generation fluids have better high temperature resistence mainly.

02-05-06, 12:42 AM
Thank you for the reply. I did some research and found the following official information on Dexron VI vs. Dexron III H:

Clutch friction stability -- improved 100 %
Clutch Durability due to fluid -- Improved 120%
Oil Film Thickness -- Increased 20%
Fluid Oxidation -- Improved 100%
Foam Aeration -- Improved 150%
Shear Stability -- Improved 200%

Part Number 88861003 (ATF 1 qt bottle)
PN 88861045 (gallon bottle)

The gallons are much cheaper at GM Parts direct.

I'm doing the ATF transfer with the "unplug the cooler line to a bucket" system in the Tech Archive. I got 15 qts. Will do it tomorrow morning and will report back.

Edit: I'd add that my current ATF has a little foam in it.

02-05-06, 03:17 AM
The last two times I've done the tranny drain, including the side cover I have filled with Mobil synthetic. What would be the result of using Dexron VI for fill the next time I drain my fluid-ending up with a mix of Mobil synthetic, Dexron III and Dexron VI? Also, does anyone know if Mobil is or will be marketing a synthetic that meets the Dexron VI specs?

02-05-06, 09:35 AM
Apparently it's a dealer only item for probably a year or two or ?

The situation is that this new Dexron VI, is above the Mercon V spec, so who knows if that means the ATF fluid companies will have to make two instead of one formula now. Dexron III will be phased out once they get licenses to produce Dexron VI.

In regards to your question of mixing--oil mixes up just fine. That's why I'm draining it to a bucket via the cooler line, with normal flow so as to not disrupt anything. It allegedly gets out the most fluid.