Author Topic: Any hazards to using synthetic Dexron VI in 60s and 70s cars??  (Read 359 times)

Offline cadillacmike68

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Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« on: November 12, 2017, 11:05:27 PM »
Are there any hazards to using synthetic Dexron VI in 60s and 70s cars?? And can I mix syn with non-syn and Dexron III/IV with VI?? Other than minor (and some not so minor - I'll Never get that stain off the garage floor!) leaks around gaskets / seals, I haven't had any transmission problems over the years and have used the internal pump to flush it a couple times - No ppwer flushing!! It just got a new bottom pan and some new fluid, but I want to know if I can use any Dexron or do I have to use the older Dexron III.

Or am I asking for trouble???
Regards,
"Cadillac" Mike
Current:
1968 DeVille Convertible
1996 Fleetwood Brougham
2009 STS NorthStar Platinum ed RWD
2011 CTS PRemiun ed Sedan RWD
Past:
2008 CTS Premium ed Sedan AWD
2005 CTS Hi-Feature Sedan RWD
2000 ElDorado ESC Hard Boot Convertible
1995 Fleetwood Brougham
1973 Sedan DeVille
1970 Fleetwood Brougham
1969 DeVille Convertible

Offline TJ Hopland

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #1 on: November 13, 2017, 03:49:59 AM »
What I have always heard is to only use 6 in stuff that came with it, everything else gets 3 including rebuilt Fords and Mopars.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline cadillacmike68

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #2 on: November 13, 2017, 09:40:47 AM »
What I have always heard is to only use 6 in stuff that came with it, everything else gets 3 including rebuilt Fords and Mopars. 

According to this GM bulletin Dexron VI is approved for use in all prior year THM transmissions:

FOR RELEASE: 2005-04-01

CONTACTS

GM Introduces New Automatic Transmission Fluid For 2006 Cars and Trucks


* New factory-fill fluid standard in all 2006 MY Hydra-Matic transmissions
* Significantly improved viscosity, shift performance and fluid durability
* Available through GM Vehicle Care products as DEXRONŽ-VI
* Approved for service application on all prior model year Hydra-Matic automatic transmissions

Pontiac, Mich. - GM, in conjunction with Petro-Canada and Afton Chemical Corporation, have developed a new, improved automatic transmission fluid for all 2006 model year Hydra-Matic automatic transmissions.

Developed for factory-fill as RDL-3434 and registered for service fill as DEXRONŽ-VI, the new fluid represents a significant improvement in automatic transmission fluids and is the direct result of GM's industry leadership in the development and production of automatic transmissions.

"For 65 years, GM has led in the design, development and production of automatic transmissions," says Tom Stephens, group vice president for GM Powertrain.

"This knowledge and experience has helped us work directly with the petroleum industry to develop a new fluid that will further accentuate the performance and reliability of GM's Hydra-Matic transmissions."

Automatic transmission fluid (ATF) is considered the life-blood of the automatic transmission.

It is used to transfer power in the torque converter and provide the pressure to apply the transmission's various clutches and bands.

It also is used to clean, lubricate and cool the components of the transmission. GM's new transmission fluid, DEXRONŽ-VI, was developed to have a more consistent viscosity profile; a more consistent shift performance in extreme conditions; and less degradation over time.

Beginning with the design and development of GM's new Hydra-Matic 6-speed rear-wheel-drive transmissions, GM Powertrain engineers determined the need for a new transmission fluid to withstand the complexity of the clutch-to-clutch transmission operation.

Additionally, GM engineers identified opportunities to improve viscosity, durability, and impact on fuel economy with a new fluid.

"The development of DEXRONŽ-VI is the first time an automotive company has worked so closely with petroleum and additive companies to develop a new fluid," says Roy Fewkes, driveline fluids group leader, GM Powertrain.

"The result is a new fluid that significantly outperforms existing fluids in every aspect. In fact, we have had to significantly extend the length of our durability tests to fully test the fluid's capability."

Internal GM tests have demonstrated DEXRONŽ-VI to deliver more than twice the durability and stability in friction tests compared to existing fluids.

It also has demonstrated superior performance in pitting, foaming, oxidation and shear stability tests.

GM will begin factory-fill of the new transmission fluid on April 4, starting with the new Hydra-Matic 6L80, produced at the Willow Run transmission facility in Ypsilanti, Mich.

DEXRONŽ-VI will be available through genuine GM Vehicle Care products at GM authorized dealerships and service centers in Summer 2005. -


So what's this bugaboo about not using it???
Regards,
"Cadillac" Mike
Current:
1968 DeVille Convertible
1996 Fleetwood Brougham
2009 STS NorthStar Platinum ed RWD
2011 CTS PRemiun ed Sedan RWD
Past:
2008 CTS Premium ed Sedan AWD
2005 CTS Hi-Feature Sedan RWD
2000 ElDorado ESC Hard Boot Convertible
1995 Fleetwood Brougham
1973 Sedan DeVille
1970 Fleetwood Brougham
1969 DeVille Convertible

Offline Mike Josephic CLC #3877

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #3 on: November 13, 2017, 03:33:57 PM »
The reply by Cadillacmike68 is correct.  In the updates of the Dexron series,
GM has always insured that new formulations are fully "backward compatible"
to all previous applications.

This question comes up every time GM makes a change and the answer is
always the same.  No worries.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
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Offline TJ Hopland

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #4 on: November 13, 2017, 11:44:13 PM »
Keep us posted on how it works out for you.   I have never tried it myself, I'm just going by what my transmission shops have told me and what I read on the forums.     A THM400 which is what I assume the original question is about wasn't a model I have specifically asked about so maybe its different than others I have had to deal with.   Maybe its a conspiracy by transmissions shops to keep using the old stuff and needing more service?   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline The Tassie Devil(le)

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #5 on: November 14, 2017, 12:11:29 AM »
More likely the ignorance of the transmission shops to keep up with new technologies.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline 35-709

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #6 on: November 14, 2017, 06:29:17 AM »
 ;D  Right!
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold
1950 Jaguar Mark V Saloon resto-mod

Offline TJ Hopland

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #7 on: November 14, 2017, 09:13:53 AM »
So you guys have been running the stuff and its working great?    For how long?   Anyone for the full 12 years? 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline fishnjim

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #8 on: November 14, 2017, 07:29:58 PM »
Something to try on that stain.   Get some Dawn dish detergent.   Put on full strength.   Brush in and let is set a bit then flush off with water.   It cleans oily stains well off concrete.   May have to repeat if it's been on there awhile.   The purple stuff isn't too bad for that either.

Offline Glen

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #9 on: November 15, 2017, 12:02:35 AM »
I never worried about it.  I used the most current Dexron in my 300,000 mile 68 ELDO.  No problems caused by that.   
Glen Houlton CLC #727 
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Offline cadillacmike68

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Re: Any hazards to using synthetic Dexron VI in 60s and 70s cars??
« Reply #10 on: November 19, 2017, 08:24:40 AM »
Glen, that's almost double the mileage on my DeVille, so I'll transition over to the VI once I get my car back.
Regards,
"Cadillac" Mike
Current:
1968 DeVille Convertible
1996 Fleetwood Brougham
2009 STS NorthStar Platinum ed RWD
2011 CTS PRemiun ed Sedan RWD
Past:
2008 CTS Premium ed Sedan AWD
2005 CTS Hi-Feature Sedan RWD
2000 ElDorado ESC Hard Boot Convertible
1995 Fleetwood Brougham
1973 Sedan DeVille
1970 Fleetwood Brougham
1969 DeVille Convertible