2000 Tahoe Transmission fluid - Should I change it?

[dman76]

Back on subject here, so since this has the original ATF which is Dex III, and since I won't be draining all of it, the Dex IV mixes with it fine, right?

 

[latvius]

If you do the procedure I did you'll get all of it out. You'll be adding dexron VI until dexron VI comes out. But either way it is the replacement for dexron III so should be just fine. I've never heard anything saying not to add dexron VI to a transmission with dexron III in it.