who has successfully used DEX VI in their old 200 4r?

[olds307 and 403]

Dr Dan Mascal suggested either Dexron 3 or 6 and not combining them. I combined them. Honestly, these 2004R, even after changing every seal, they leak somewhere. I use a combination of the cheapest Dexron 3 to colour and Tractor Trans Hydraulic fluid. It is a 5W30 or 10W30 and basically eliminates leaks and shifts fine.

 

[Built6spdMCSS]

I've read Dex VI is the synthetic version of Dex III. I run Dex III in everything GM I have, that being two cars with T56 6spd Manuals, and my truck with the 4L80E.

well its not just ATF its zinc in oil as well. this has been the biggest sh*t storm of all i had done to my car since the 305 kicked. i bought this for 2900.00 in early 21' that last i looked can't get for less than 4k now, from pace performance SHIPPED.. the long block is incredible. https://paceperformance.com/i-23924...mc-full-size-trucks-g-van-up-to-7200-gvw.html

its the same debate as ATF add zinc (especially if flat tappet cam)/ don't need it.... asked my mechanic other day should i get zinc additive to go along with mobile 1 full synth as my 2nd oil change with 2k miles on it and its not just that. its also should i use full synth @ 2k miles. this has me runnin mad. lol

good thing i have a spare high performance 200 4r in the shed sittin 20 yrs waiting to be used just in case... i'm feeling like a crash test dummy when it comes to this post topic. lol

See here's the thing with zinc, it's supposed to help lubrication. ATF has friction modifiers in it to ADD friction to certian areas, as in your Clutches to Steels in the drums, so trying to see where the zinc will help here..

 

[L05edSS]

I've read Dex VI is the synthetic version of Dex III. I run Dex III in everything GM I have, that being two cars with T56 6spd Manuals, and my truck with the 4L80E.

See here's the thing with zinc, it's supposed to help lubrication. ATF has friction modifiers in it to ADD friction to certian areas, as in your Clutches to Steels in the drums, so trying to see where the zinc will help here..

the zinc part was just a side topic in my complaint of stupid simple stuff getting too complex from what used to be. aside from the OP at hand its motor oil as well.

 

[86LK]

DEXRON - Wikipedia

en.wikipedia.org

Dexron VI is of a slightly lower viscosity when new compared to the prior Dexron fluids (a maximum of 6.4 cSt at 100 °C for Dexron VI and 7.5 cSt for Dexron III), but the allowed viscosity loss from shearing of the ATF during use is lower for Dexron VI, resulting in the same lowest allowed final viscosity for both Dexron III and VI (5.5 cSt) in test.[22] In reality most of the DEXRON-III fluids typically sheared to about 4.2 cSt in use. The lower, more stable viscosity improved pumping efficiency within the transmission and fluid stability over life. Since Dexron VI is not allowed to thin out (lower its viscosity) as much as Dexron III during use, it requires the use of higher-quality, more shear-stable (less prone to thinning while in use) formulations.[23] The container rear label reads "Full Synthetic Automatic Transmission Fluid"; however, the base oil composition is not stated. The current GM specification that defines the fluid is GMW16444, which superseded the original specification, GMN10060.

All Dexron-III (H) licenses expired permanently at the end of 2011, and GM now supports only Dexron-VI fluids for use in their older automatic transmissions.[24] Aftermarket fluids asserted by their manufacturers to meet Dexron-III(H) and earlier standards continue to be sold under names such as Dex/Merc. These fluids are not regulated or endorsed by GM

DEXRON - Wikipedia

en.wikipedia.org

note the specification stipulation of 'K' below

On August 1, 2016, GM released the Dexron III (K) fluid specification (GM Spec GMW17639) as a fluid to support older GM manual transmissions and power steering systems requiring the previously discontinued Dexron-III(H) fluid.

WARNING:The additive package for automatic transmissions has been removed from this fluid; do not use it in any automatic transmission.

 

[ck80]

DEXRON - Wikipedia

en.wikipedia.org

Dexron VI is of a slightly lower viscosity when new compared to the prior Dexron fluids (a maximum of 6.4 cSt at 100 °C for Dexron VI and 7.5 cSt for Dexron III), but the allowed viscosity loss from shearing of the ATF during use is lower for Dexron VI, resulting in the same lowest allowed final viscosity for both Dexron III and VI (5.5 cSt) in test.[22] In reality most of the DEXRON-III fluids typically sheared to about 4.2 cSt in use. The lower, more stable viscosity improved pumping efficiency within the transmission and fluid stability over life. Since Dexron VI is not allowed to thin out (lower its viscosity) as much as Dexron III during use, it requires the use of higher-quality, more shear-stable (less prone to thinning while in use) formulations.[23] The container rear label reads "Full Synthetic Automatic Transmission Fluid"; however, the base oil composition is not stated. The current GM specification that defines the fluid is GMW16444, which superseded the original specification, GMN10060.

All Dexron-III (H) licenses expired permanently at the end of 2011, and GM now supports only Dexron-VI fluids for use in their older automatic transmissions.[24] Aftermarket fluids asserted by their manufacturers to meet Dexron-III(H) and earlier standards continue to be sold under names such as Dex/Merc. These fluids are not regulated or endorsed by GM

DEXRON - Wikipedia

en.wikipedia.org

note the specification stipulation of 'K' below

On August 1, 2016, GM released the Dexron III (K) fluid specification (GM Spec GMW17639) as a fluid to support older GM manual transmissions and power steering systems requiring the previously discontinued Dexron-III(H) fluid.

WARNING:The additive package for automatic transmissions has been removed from this fluid; do not use it in any automatic transmission.

So, sounds like a sh*t sandwich from GM, unsurprising.

Either use a thinner inferior fluid for older cars penalizing people who keep things changed, or, run a better viscosity fluid that no longer has the additives and you get a kick to the nuts.

Hmm. Wonder what the additive package is and if you can get it separately from someone to add to the manual formulation.

 

[86LK]

So, sounds like a sh*t sandwich from GM, unsurprising.

Either use a thinner inferior fluid for older cars penalizing people who keep things changed, or, run a better viscosity fluid that no longer has the additives and you get a kick to the nuts.

Hmm. Wonder what the additive package is and if you can get it separately from someone to add to the manual formulation.

don't forget it also said...
Aftermarket fluids asserted by their manufacturers to meet Dexron-III(H) and earlier standards continue to be sold under names such as Dex/Merc.

 

[Vilanus]

mine is 1986 factory built with 72k miles and filter changed once or twice since bought 20 yrs ago. never had any issues and shifts fine. i'm getting mixed messages using this in my trans. autozone stated GM updated its recommendation for dex 6 in my specific car and word on the street is all over the map so i ask in this manner.

Dex VI is superior in every way, no reason not to use it over dex III.

Also since the dex III certification expired decades ago, supplyers can put anything in there and call it dex III