2004 Tahoe - ATF type/mixing?

[kevshoe]

I have a 2004 Tahoe LS with about 150,000 miles on it. Was going to do a ATF swap (not changing the filter, just trying to get cleaner fluid in there). I know it calls for Dex 3, but would it be ok to put Dex 6 in there? Is it ok to mix Dex 3 and Dex 6?

 

[Spaceman Spiff]

Unless your pan has a drain plug, you have to remove it to change the fluid. Pretty silly not to change the filter while it’s off.
Just did my ‘05, 136,*** miles. Used dex 6 and a bottle of Lucas.

 

[08grey]

I think your truck has a drain plug. Curious to see what fluids others are using?

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[jcjc]

GM officially says to use Dex VI during service, any proportion or mix with Dexron III is ok. You will find transmission fluids on the store shelves which are designated for use with transmissions requiring Dexron III/Mercon fluids, if you read between the lines, these are the old Dexron III/Mercon formulas, just GM (and Ford) no longer officially licenses them to market under those names.

 

[HiHoeSilver]

Unless your pan has a drain plug, you have to remove it to change the fluid. Pretty silly not to change the filter while it’s off.
Just did my ‘05, 136,*** miles. Used dex 6 and a bottle of Lucas.

This is not true. The best way to change the fluid, even if you ARE going to drop the pan and do the filter is to pump it out via the cooler line.

 

[SnowDrifter]

^^Which introduces a real possibility of adding contaminants to the system and/or running the sump dry. I don't agree with that method

A couple drain/fills of the pan is all you need. Can do some math to determine how much "new" fluid is in the system.

For fluids, I've used amsoil torque drive, amsoil multi vehicle atf, valvoline maxlife (the normal stuff, not high mileage), and redline d4 atf in mine. It seems to prefer the thicker stuff: Amsoil and redline over the thinner valvoline(I also have 140k on mine, parts are wearing, tolerances are larger). But even then, the valvoline never caused issues. Just shifted a little too soft for my tastes if the trans got got in traffic or something (I have a tune, shift firmness set higher).

 

[sonic_the_hedgeh]

I had my fluid flushed with dextron 6. It is compatible with dextron 3. The stock pans don't have a drain plug. Mine has one I was going to change myself but then discovered it was stripped. So I opted to go to a shop and just flush it. Much better now.

2004 GMC Yukon Denali

330,000 and still runs great!

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[inmypassatlife]

Valvoline Maxlife