Conventional 5W-30 No Longer Available?

AuroraGirl said:

It brings up Dexron III but in the new package(since 2006)
That MANUAL TRANSMISSION AND TRANSFER CASE (not to be confused with a synthetic newer fluid sold by GM under similar wording) fluid is Dexron III
Go buy one, its even dyed red. Flows like ATF. Is ATF. The SDS I even scoured a modern one jsut to check, and its still mostly a petroleum byproduct and red etc
Oreillies offers several jugs of fluids that say DEX (or DEX III) and Mercon
But Dexron III is no longer policed, anyone can put it on their label, and Mercon (original) is no longer made, period, but Mercon V is fords replacement which is policed unlike mercon. that being said, Ive used that valvoline in my e4oD and my 4t65e. Worked fine.

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I use the Blue Valvoline Dex III bottle above from O'reilly. 4L85E still shifts like a TH400 with a shift kit.

L31MaxExpress said:

I use the Blue Valvoline Dex III bottle above from O'reilly. 4L85E still shifts like a TH400 with a shift kit.

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thats great

AuroraGirl said:

It brings up Dexron III but in the new package(since 2006)
That MANUAL TRANSMISSION AND TRANSFER CASE (not to be confused with a synthetic newer fluid sold by GM under similar wording) fluid is Dexron III
Go buy one, its even dyed red. Flows like ATF. Is ATF.

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I wouldn't have thought it would be. My assumption was that it would be more like an 80/90 gear oil with that name. I'm new to GM stuff and automatic transmissions. This truck being the first one I've had. I've always built subaru's with manuals. I work at orilley's selling and delivery parts to shops and go by what the computer says.

This is great conversation and very timely.
A guy worked for 25 or so years ago has 4 wiedamann cnc turret punch presses.
And some other machinery as well.
All calling for dexII or dex III.
Pretty common with old CNC punch presses and press brakes.
When they were new, plus or minus .002 was easy.
He still gets plus or minus .006 out of them.
Mainly through wringing the slop out of the lead screws when he programs them.
To replace all of that machinery would be insanely expensive.
He cant afford it.
He needs to get about ten more years out of these things so he can retire.
The problem is that nothing, nothing barfs oil like an old CNC punch press.
About 5 gallons a week.
Which is about a hudred bucks a week on cat litter in case you were wondering about that ratio!
OSHA approved non clumping scent free cat litter of course.
Safety First.
We have hashed this over a few times on the phone and I dont have the faintest scrap of an idea what to tell him.
I am pretty familiar with all of the oils.
Ya got motor oil. That goes in the engine.
Dont use it for cooking.
Ya got transmission oil.
Some of that goes in chevys and some of that goes in fords.
Get it straight.
Dont cook with that either.
Ya got baby oil. normally used when you come across a dried out baby.
Unless you payed extra money in Vegas
Pretty damn easy.
Then you got the olive oil thing.
Pure olive oil is for cooking.
Extra virgin is for salads an emulsions.
Vegatble oil is that jug that sat on top of grandmas fridge with a layer of horror crud caked on it.
Why do you guys make such a simple thing so complicated?
Put the motor oil in the engine.
Put the ford goop in the ford.
Put the chevy goop in the chevy.
Dont fry the babies in olive oil and dont blend them into a salad.
Dont use grandmas 30 year old veggie oil for anything.
What you get up to in Vegas with Coconut oil is a whole different subject.
You ******* need to stop ruining salads and charring the outside of barbequed babies.
It is pretty damn straightforward simple chemistry.

AuroraGirl said:

but it should be understood that dexron VI is higher viscosity than Dexron III at temperature,

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If the above is true at all, it isn't universally true.
For the two fluids in the PDFs, the Dex III has viscosity of 7.66 cST at 100C and the Dex VI 5.95 cSt at the same temp.

GM graph on the viscosity stability over the course of time, A is Dex 3, B is Dex VI, which I assume then that its more about the break down over time which occurs rapidly relatively speaking in dex 3 but isnt seen very much in 6. i assume some of the aftermarkets, even if they didnt do this test, maybe can do considerably better since they often have blends etc themselves of synthetic stuff

Alot of good thoughts in this thread.

My personal preference is Valvoline Maxlife as is is supposedly fully synthetic like Dex VI, but with a thicker viscosity like Dex III.

If it has the same resilience as AuroraGirl's chart for Dex VI over time.... it would definitely be a fluid to go to. Dex VI is thinner than Dex III, but that refers to new fluid testing. Old trans fluid can can be quite thin, possibly consistent with the chart observation.

I too would trust an oil company over the company that brought us Dexcool.


As far as Oils, I would stay far away from anything that smells like crayons. Paraffin wax based oils historically sludge up. I like to get the "synthetic" Warren Petroleum manufactured store brand oil from walmart or Meijers.

Also Synthetics oils are supposed to thicken as their additive package depletes, where as Conventional oils thin as their additive package depletes.

Doesn’t surprise me since the majority of cars now require it the companies aren’t going to keep making it to sell 20 bottles a month. I haven’t noticed but I also use synthetic in most everything. The Buick gets whatever is cheapest but even that most times ends up being a blend.

Wiscoburban said:

Doesn’t surprise me since the majority of cars now require it the companies aren’t going to keep making it to sell 20 bottles a month. I haven’t noticed but I also use synthetic in most everything. The Buick gets whatever is cheapest but even that most times ends up being a blend.

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you got a fleet farm or a farm and fleet near you? You are also in moo-land so I figured id mention. You can get Farm and fleet(prob fleet farm) oil in 12 case of conventional in various weights. I use that oil since its a group 3 oil from


Is cheap as it gets around me at least.

I seen this coming to the industry.