Good Morning all: Years ago GM transmissions too Dextron fluid, I think it was green in color.
I don't see it on shelves at auto stores and I seem to remember it was replaced by the fluid used by Ford ( the red one).
What is the recommended transmission fluid these days ?

Thanks Joe JCVCUTLASS

 

Well, you just opened a can of worms😁. First, what transmission? One of the more current specs is Dexron 6 that is backward compatible but some have complained of issues, I have not seen any shift issues. One issue using a synthetic and thinner fluid like Dexron 6 in an old trans, is leaks. Many modern transmissions, including I assume GM's new 10 spd use synthetic fluid as thin as water but no doubt have much better designed seals. The ZF 8 speed in my Challenger has no dipstick, can only be properly checked with a scan tool and uses expensive super thin ZF specific and expensive green fluid. Dodge says it is a lifetime fluid, ZF says it needs changed in severe service conditions. Problem with servicing the Dodge variety is the filter is part of the pan and makes a very expensive service. A great transmission by the way and since I tow a boat with it, eventually I will bite the bullet. May get my BIL to service it on lift where he teaches mechanics.

 

As far back as I can remember all transmission fluid was red. I actually use the Ford stuff (type F) in my transmission. Typically people run Dex III or Dex/Mercon

 

What Eric said. As far as I know all Dextron are compatible with each other so any will work. I personally wouldn't use a synthetic with anything that is built with cork gasket seals on a older transmission.....Tedd

 

For what car and what transmission?

As a general rule any GM before 1999 works fine with DEXRON III/MERCON III. I would personally be leery of using V or VI formulations in anything made before then.

Type F was formulated for Fords. It can be used in other transmissions for firmer shifts. B&M Trick Shift was basically Type F dyed blue.

 

Any fluid made today is far superior to anything available when these cars were new.

I use the Valvoline synthetic fluid from AutoZone in my personal vehicles. It’s around 30 bucks a gallon, occasionally you can find it on sale for 24.

I wouldn’t hesitate to use the Valvoline stuff in anything older than about 10 years. Much newer than that, it’s probably best to use the specified fluid.

 

Wasn't Whale Oil one of the important additives removed quite a few years back? My understanding is took quite a few years to find a decent replacement. Yeah, the Valvoline Maxlife Dexron 6 worked fine for me and is cheap at Walmart.

 

It supposedly still is in some Japanese-spec fluids. Unlike us, their whaling industry never got shamed into going away.

Whale oil is why older fluids stunk so bad if they got scorched a little. But it was perfect for the application. Right temp range, right coefficient of friction, right lubricity, but it got the wrong kind of attention from self-flagellating activists.

 

IF you have a ST300, TH350 or TH400 you MUST use Dexron III. Dexron has ALWAYS been red. Ford used type F, which you should NEVER use in your GM transmission. Hope that helps. Take care.

 

Years ago, back in the late '40s, '50s, and '60s Sperm whale oil was used as an additive to aid in lubricity. Lubegard is supposed to be a synthetic version of sperm whale oil. Hope that was helpful. Take care.

 

People have used type F fluid in GM and Mopar applications for years. If you read the instructions for shift kits, it specified using Type F fluid due to the lack of additives that smoothed the shift.

The crappiest fluid made 20 years ago is superior to the best quality fluid made when these cars were new. The refineries are constantly improving the additive package, it’s no big deal today to get 200-300k miles from a automatic before needing an overhaul, if you got half that mileage in the 69s-70s that was impressive.


When I worked at Coan years ago one of my jobs was to tear down Powerglides, Dave Coan has been hoarding those since the mid 70s.I have taken apart hundreds of core transmissions, it’s easy to tell the ones that had been sitting in a junkyard or warehouse for decades. The fluid is gummy, the valve bodies are full of varish like crud, you just don’t see that with modern fluids.