Dex III or Dex VI

[tyhuck]

I have been searching for a while on what fluid I can run in my truck, but I keep getting mixed answers. Some people say that Dex VI is a superior fluid compared to III and that it is better to use VI to top off my transmission.

 

Others say that any trans built to use III can not use VI because the tollerances are not tight enough to use the VI, and that VI has a thinner viscosity and will not lube an older trans as well as III.

 

I have also seen that you can mix the two, and that it bad to mix the two. Obviously its not good to mix III in with IV on a trans that calls for VI specifically, but is it bad to mix IV in with III in the older ones.

 

I ask because my truck has 102K on it and I have no clue as to when or if its has had a transmission service, so Im getting ready to do one. Its an 05 with a 4L60E. I dont want to screw up my trans by putting the wrong fluid in it. I know that Dex III was used up until late 05 when the 06 models came out. I would however like to use the most updated fluid available. And since GM doesnt regulate Dex III compatible fluids anymore, I want to make sure Im using a GM approved fluid.

 

The guy at NAPA sold me 5 quarts of Valvoline Dex VI but I want to make sure its OK to use this before I drop the pan and end up stranded with the wrong fluid.

[Jsdirt]

If it's a 1500, I'd just run this & be done with it. http://www.amsoil.com/catalog.aspx?code=ATLQT-EA

 

But on that note, that's the same stuff I run in my '07 which can use nothing but VI. I think there was a bulletin out saying VI superceded all others, which I would imagine to be the case anyway.

[00Silverado4x4]

Yes Dex VI is backwards compliant for all previous Dexrons (II, III, IV). I thought Dex VI was already required for trucks in 2005, guess I was wrong on that one.

[Black02Silverado]

You can use the dexron VI with no issues, as stated above it is backward compatible.

[tyhuck]

Yes Dex VI is backwards compliant for all previous Dexrons (II, III, IV). I thought Dex VI was already required for trucks in 2005, guess I was wrong on that one.

 

 

From what I can tell, it was, but it started in the 06 models which were released late in 05.

[txab]

Use Dex VI and quit worrying