Is it true that Dexron III is already fully synthetic?

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Patman

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I've heard more than one person tell me over the years that fully synthetic trans fluid is uneccessary if your car already runs Dexron III, since Dexron III is already a fully synthetic fluid. Is this true? If it is, why is it so cheap to buy compared to fully synthetic ATF?
 
Found this on an Esso product data sheet:

'ESSO ATF MERCON V/DEXRON-III is manufactured from high quality petroleum base stocks, carefully blended with selected additives.'

Very unlikely
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Mercon-V and Dexron 3 are not even compatible.

Ford's Mercon-V specificiation is a Group III synthetic, commonly sold as a synthetic blend, or partially synthetic ATF.
Quaker State has Multi-Car ATF, and 4x4 synth blend that is compatible with Mercon-V, Mercon, Dexron III, etc...

Pennzoil has Mercon-V which is also compatible with the above,

HOWEVER Ford's Motorcraft Mercon-V is only compatible with Mercon-V due to a different additive package.

Mercon-V, by the very specification itself, is a synthetic blend.
 
Dexron III is a Group II+ fluid. Mercon V and ATF+4 are Group III fluids.
 
Most of the time I see Dexron-III/Mercon ATF, so I know its at least a group II formulation.

Mercon-V's spec calls for it to be a least a synthetic blend (group III or otherwise) to handle the overheating condition that causes "shudder" in the 4R70W.

Contrastly, the 4R100 uses Mercon but then again the 4R100 learns the driver's driving style and adjusts accordingly. There's a TSB that calls for reprogramming the PCM to eliminate the shudder in 4R70W vehicles.
 
There are Group I Dexron III/Mercon products out there. The spec is performance, and for some if they can sqeak through it with additives, so be it. I prefer group II+
 
Dexron III does not necessarily equal synthetic. Dexron III indicates a certain additive package and performance measures for GM transmissions.

Dexron three may contain a Group II, III, or Group IV base with small amounts of Group V's.

I just posted a chemistry topic on ATF's in the Interesting Article thread.


BTW, expensive analysis using NMR and certain spectrographic analysis is the only way to determine what the base oils might be.

[ February 13, 2003, 11:19 AM: Message edited by: MolaKule ]
 
quote:

Originally posted by G-Man II:
Dexron III is a Group II+ fluid. Mercon V and ATF+4 are Group III fluids.

Is the Chrysler ATF+4 fully synthetic? It is required in my '02 Grand Cherokee V8 for the trans and transfer case. If sythetic, I will not change the TC until 30K and the trans until 60K.

Thanks in advance!
 
There is no gurantee that the latest Chrysler spec is a full synthetic. I do know that various esters and other friction modifiers were added to the base oils (whatever they may be) in order to bring the older spec fluids up to the 4+ level.
 
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