4L60E ATF

[mattd]

What atf do I use in my 2000 Sierra w 5.3?

 

the internet says both dex3 and 6.
 

The guy at the parts store looked it up and said dex6. 
 

my dipstick says dex3. 
 

as smart as the internet is, I’m leaning towards the dipstick!

[ryank1]

Dex 6 is backwards compatible with Dex 3, but you can't use Dex 3 in a Dex 6 application per GM.  So to answer your question, you can use either one and per GM you can mix them for you application.

[Adamog45]

either one

 

[CamGTP]

The dex 3 is usually cheaper as well, so I run that in all the older cars.

[drdiesel2010]

Dexron 6

[dgstarr63]

Dexron 6 is a synthetic ATF that will withstand more heat than Dexron 3.  I use Valvoline full synthetic Max Life Dex/Merc which meets Dexron 6 specs.

[Black02Silverado]

Dexron VI will work fine.  No issues and that is what I switched my 2002 Silverado over to when it came out which is AMSOIL's ATL fluid.