DextronIII vs Dextron VI
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Btw, it's "Dexron".
Burning Brakes
Joined: Jul 2006
Posts: 763
Likes: 45
From: Long Grove IL
Here's the official word on it..
Originally Posted by GM #04-07-30-037D
MANUAL TRANSMISSIONS / TRANSFER CASES and POWER STEERING
The content of this bulletin does not apply to manual transmissions or transfer cases. Any vehicle that previously required DEXRON®-III for a manual transmission or transfer case should now use P/N 88861800. This fluid is labeled Manual Transmission and Transfer Case Fluid. Power Steering Systems should now use P/N 9985010 labeled Power Steering Fluid.
Consult the Owner's Manual or Service Information (SI) for fluid recommendations.
Some of our customers and/or General Motors dealerships/Saturn Retailers may have some concerns with DEXRON®-VI and DEXRON®-III Automatic Transmission Fluid (ATF) and transmission warranty claims. DEXRON®-VI is the only approved fluid for warranty repairs for General Motors transmissions/transaxles requiring DEXRON®-III and/or prior DEXRON® transmission fluids. Please remember that the clean oil reservoirs of the J 45096 - Flushing and Flow Tester machine should be purged of DEXRON®-III and filled with DEXRON®-VI for testing, flushing or filling General Motors transmissions/transaxles.
DEXRON®-VI can be used in any proportion in past model vehicles equipped with an automatic transmission/transaxle in place of DEXRON®-III (i.e. topping off the fluid in the event of a repair or fluid change). DEXRON®-VI is also compatible with any former version of DEXRON® for use in automatic transmissions/transaxles.
The content of this bulletin does not apply to manual transmissions or transfer cases. Any vehicle that previously required DEXRON®-III for a manual transmission or transfer case should now use P/N 88861800. This fluid is labeled Manual Transmission and Transfer Case Fluid. Power Steering Systems should now use P/N 9985010 labeled Power Steering Fluid.
Consult the Owner's Manual or Service Information (SI) for fluid recommendations.
Some of our customers and/or General Motors dealerships/Saturn Retailers may have some concerns with DEXRON®-VI and DEXRON®-III Automatic Transmission Fluid (ATF) and transmission warranty claims. DEXRON®-VI is the only approved fluid for warranty repairs for General Motors transmissions/transaxles requiring DEXRON®-III and/or prior DEXRON® transmission fluids. Please remember that the clean oil reservoirs of the J 45096 - Flushing and Flow Tester machine should be purged of DEXRON®-III and filled with DEXRON®-VI for testing, flushing or filling General Motors transmissions/transaxles.
DEXRON®-VI can be used in any proportion in past model vehicles equipped with an automatic transmission/transaxle in place of DEXRON®-III (i.e. topping off the fluid in the event of a repair or fluid change). DEXRON®-VI is also compatible with any former version of DEXRON® for use in automatic transmissions/transaxles.
Burning Brakes
Joined: Dec 2003
Posts: 1,243
Likes: 5
From: Loveland CO
Dex VI is not compatible with Corvette manual transmissions.
* GM Manuel transmission fluid (listed above)
* Dex III from the parts store (I am running Valvoline DexIII) (amsoil and mobile are Synthetic, off the shelf Dex III at the parts store may not be)
S
* GM Manuel transmission fluid (listed above)
* Dex III from the parts store (I am running Valvoline DexIII) (amsoil and mobile are Synthetic, off the shelf Dex III at the parts store may not be)
S
Thread Starter
8th Gear
Joined: Sep 2014
Posts: 8
Likes: 0
From: Ontario
Dexron VI
Thanks
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Burning Brakes
Joined: Oct 2004
Posts: 984
Likes: 23
From: Florence SC
I've been running the Dexron IV in my 99 FRC now for over a year with no problem, fact is the car shifted better when I went to the new fluid. I was advised by a retired Corvette GM engineer (here on the forum) that the Dexron IV was fine to use.
You might want to read this:
https://www.corvetteforum.com/forums...-vs-dexvi.html
You might want to read this:
https://www.corvetteforum.com/forums...-vs-dexvi.html
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
It's not confusing at all. It relates to where if synchromesh (88861800) is not available, it says use DexIII, but do NOT use DexVI in the specified transmissions.
Now you're entertaining a dealer's, contradiction of the very document GM published which, by the way was published at the time, primarily regarding certain Cadillac, Hummer and Saturn models with manual transmissions?
Your car, your call. Good luck.
Last edited by LoneStarFRC; Oct 4, 2014 at 01:00 AM.
Team Owner
Joined: May 2001
Posts: 87,302
Likes: 1,583
From: Western NY
There have been multiple discussions of manual transmission fluid usage, here on the Forum. The differences hinge on the earlier transmissions having "paper blocking rings" that are not compatible with synthetic transmission fluid, which Dexron VI is......
(Dexron III is not synthetic)
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
There have been multiple discussions of manual transmission fluid usage, here on the Forum. The differences hinge on the earlier transmissions having "paper blocking rings" that are not compatible with synthetic transmission fluid, which Dexron VI is......
(Dexron III is not synthetic)
(Dexron III is not synthetic)
My previous post was not clear enough to re-state what has been said throughout this thread.
The answer provided in this thread; and supported by the GM Bulletin, is that Dexron VI should not be used in a standard/manual transmission. It goes on to state that Dexron VI can be used in the automatic transmission.
Is it possible that when stating in his original question, "99 C5 standard transmission"; he was referring to his standard transmission being in fact an automatic?
Dannyman
Premium Supporting Vendor
Joined: Aug 2001
Posts: 5,364
Likes: 38
From: King George VA
If you have an automatic, then the newer dexron VI would be suitable, but I personally would still use an aftermarket dexron III as the dexron VI has a lower viscosity then the dexron III and I'm personally not impressed with the basestock performance in dexron VI. Like many fluids, the dexron VI was introduced to lower viscosity, lower friction and improve GM's net CAFE (fuel mileage rating).
For what its worth, I use this in my manual:
AMSOIL Torque-Drive Synthetic Automatic Transmission Fluid (Product Code ATD1G)
__________________
C66 Racing #66 NASA ST2, SCCA T2
AMSOIL Dealer (Forum Vendor)
AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
C66 Racing #66 NASA ST2, SCCA T2
AMSOIL Dealer (Forum Vendor)
AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
Thread Starter
8th Gear
Joined: Sep 2014
Posts: 8
Likes: 0
From: Ontario
Hi folks. I do have manual. I've been to 4 GM Chev Olds dealerships in my area. Three say Dexron VI and one said GM Manual transmission fluid . I've contacted GM directly and got no response.
Thanks for the bulletin
Thanks for the bulletin
Melting Slicks
Joined: Jun 2013
Posts: 3,473
Likes: 691
From: West Virginia
Anyone have any idea why this bulletin says it does NOT apply to manual transmissions?
"Originally Posted by GM #04-07-30-037D
MANUAL TRANSMISSIONS / TRANSFER CASES and POWER STEERING
The content of this bulletin does not apply to manual transmissions or transfer cases."
Also, I would like to understand the "paper blocking rings" statement. Any paper based product would last about 5 seconds in a gearbox. Blocking rings take a beating, and years ago sintered iron was commonly used.
My '98 C5 has had Mobil 1 synthetic ATF in the 'box almost from new and at 75k everything works fine. Only "issue", if it called be called that is the shift is in fact a bit smoother and easier when the 'box is still cold. I may try dino oil next time. Wish it would shift like our Subaru which runs 75/90 in the front transaxle. I use Delvac, and the shifts are buttery.
Mine is an early enough C5 (delivered 9/97) to have an actual Borg Warner built box. Any difference there I wonder? Though everything I have read says Tremec made the boxes exactly the same as the originals.
"Originally Posted by GM #04-07-30-037D
MANUAL TRANSMISSIONS / TRANSFER CASES and POWER STEERING
The content of this bulletin does not apply to manual transmissions or transfer cases."
Also, I would like to understand the "paper blocking rings" statement. Any paper based product would last about 5 seconds in a gearbox. Blocking rings take a beating, and years ago sintered iron was commonly used.
My '98 C5 has had Mobil 1 synthetic ATF in the 'box almost from new and at 75k everything works fine. Only "issue", if it called be called that is the shift is in fact a bit smoother and easier when the 'box is still cold. I may try dino oil next time. Wish it would shift like our Subaru which runs 75/90 in the front transaxle. I use Delvac, and the shifts are buttery.
Mine is an early enough C5 (delivered 9/97) to have an actual Borg Warner built box. Any difference there I wonder? Though everything I have read says Tremec made the boxes exactly the same as the originals.
Last edited by jackthelad; Oct 31, 2014 at 12:14 PM.
Burning Brakes
Joined: Jul 2006
Posts: 763
Likes: 45
From: Long Grove IL
Anyone have any idea why this bulletin says it does NOT apply to manual transmissions?
"Originally Posted by GM #04-07-30-037D
MANUAL TRANSMISSIONS / TRANSFER CASES and POWER STEERING
The content of this bulletin does not apply to manual transmissions or transfer cases."
"Originally Posted by GM #04-07-30-037D
MANUAL TRANSMISSIONS / TRANSFER CASES and POWER STEERING
The content of this bulletin does not apply to manual transmissions or transfer cases."