Trans oil and filter change Dex 3 or 4

[jimweis]

2004 Tahoe with 100,000 on it fluid was changed 50,000 ago. Should I use Dexron3/Mercon or Dexron 4?
Thanks in advance.

 

[swtz71]

I would have to say 3

 

[gdddup]

probably dex 3. or dex 6 if its newer. check the dipstick it will tell u for sure
dexron 4 is for chryslers

 

[Ironman1979]

mercon 4 is for chryslers.. thats what my durango takes

 

[ScottyBoy]

05 and newer, Dexron 6 is required. 04 and older, Dexron 3 is what was used originally. You can either go back with 3 or use the 6. Dexron 6 is backwards compatible. It more that exceeds the specs fir Dexron 3, so it can replace it. But Dexron 3 cannot replace the Dexron 6 on a 2005+.
I flushed mine and filled it with Dexron 6. I noticed a slight improvement with shifting, plus it runs about 10 degrees cooler with the 6 instead of the 3. The Dexron 6 is much more expensive than the 3, but it is a far superior product. Look up Dexron 6 on google and you will learn all the improvements the 6 has versus the 3. I looked it up and that's what influenced me to switch over.
Also, no GM dealer will put 3 in your truck if they service it, they only sell the Dexron 6 now.