So many years ago, I think on BITOG, they said that the AT II was better than the ATF even in transfer cases on the non Auto systems. So I've been using it for years. Now I read that the DEX VI is the recommended fluid. Does anyone know the difference between the fluids, and will (did) it do harm to the TC? Thanks
Autotrac II in Non Auto SD Transfer Case?
- Thread starter Quadrasteer
- Start date
AFAIK AutoTrak just needs some friction modifiers. It's essentially a limited grip that can chatter otherwise (although it uses basically auto transmission frictions and mashes them together with varying force)
The FM won't hurt a 'case that doesn't need them.
I'd say Dex VI recos are a CAFE thing and an availability thing -- GM essentially considers basic Dex dead to them because VI is reverse compatible.
If a 'case calls for VI, you could run Dex/Merc, MercV, +4, etc. I wouldn't personally try a ULV, though -- potentially too thin. If it's not an "Auto" unit it just. needs. a. light. oil.
NP261 and 263 should be run on 5W20 or 5W30 despite any manufacturer recos
The FM won't hurt a 'case that doesn't need them.
I'd say Dex VI recos are a CAFE thing and an availability thing -- GM essentially considers basic Dex dead to them because VI is reverse compatible.
If a 'case calls for VI, you could run Dex/Merc, MercV, +4, etc. I wouldn't personally try a ULV, though -- potentially too thin. If it's not an "Auto" unit it just. needs. a. light. oil.
NP261 and 263 should be run on 5W20 or 5W30 despite any manufacturer recos
I have a slightly similar but not exactly the same situation. In 2008 GM started installing Magna Powertrain transfer cases. In 2007 the auto transfer cases were using Auto-Trak II. The mechanics of the day suggested using Auto-Trak II on any automatic transfer cases, including the Magna Powertrain ones. GM just asked for Dex 6.
Fast forward to 2025. I have been using Auto-Trak II for 17 years, but rarely have used the auto feature. I have used it a lot in deep snow in the manual mode. The Magna Powertrain transfer case has 275,000 miles on it. It certainly didn’t do any harm functioning in the manual mod with Auto-Trak II. The only down side I saw is that it’s a lot more expensive than Dexron 6.
Fast forward to 2025. I have been using Auto-Trak II for 17 years, but rarely have used the auto feature. I have used it a lot in deep snow in the manual mode. The Magna Powertrain transfer case has 275,000 miles on it. It certainly didn’t do any harm functioning in the manual mod with Auto-Trak II. The only down side I saw is that it’s a lot more expensive than Dexron 6.
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Mods, here is what a bottle of Auto-Trak II looks like with the correct spelling.
I just yesterday used the Auto-Trak (LOL) and put the new Valvoline 4X 75-90 Gear Oil (with LS) in 2 front and rear diffs. 3 that didn't need the LS. I'm batting a thousand....You read one thing and then with a little more research it changes. So should I drain the AT II out and use the Dex 6? With 3 oil changes since it was new, the AT II has been in there for over 130k miles.
By the way, what vehicle is this?
'02 Sierra Denali AWD 4WS. Is there a better replacement for DEX III? It's had the AT II in it since it's first low mileage oil change (130k ago), oil came out this last time like it was new.
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Dex III has been superseded by Dex VI. I have found my Auto-Trak II looks new after about one year/ 10,000 miles and is discoloured, losing its blue color after 2 years/ 20,000 miles. I’ve been changing every two years. You can certainly use Dex VI in yours unless you want to continue with what worked fine in the past.
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