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2017 Corvette / ACDelco MTF / 6.4k mi #4529197
09/29/17 09:12 AM
09/29/17 09:12 AM
Joined: Apr 2010
Posts: 13,534
Chicago, IL
dparm Offline OP
dparm  Offline OP
Joined: Apr 2010
Posts: 13,534
Chicago, IL
GM recommends changing the transmission fluid after every 15 hours of track use, which was 7 track days and 6,392 miles for me.

Blackstone was actually quite impressed with the results since they typically expect assembly contamination and extra metal from break-in. Viscosity was almost out of grade but overall this stuff held up pretty well. Undecided if I want to step up to a more stout fluid.



Code:
OIL             ACDelco MTF
MILES IN USE    6,392    
MILES           6,392 
SAMPLE TAKEN    9/22/17  

ALUMINUM        11       
CHROMIUM        1      
IRON            82      
COPPER          22      
LEAD            1     
TIN             1        
MOLYBDENUM      2      
NICKEL          2       
MANGANESE       35      
SILVER          0       
TITANIUM        3     
POTASSIUM       3       
BORON           46       
SILICON         16       
SODIUM          9     
CALCIUM         0    
MAGNESIUM       1     
PHOSPHORUS      160     
ZINC            11     
BARIUM          3
     
INSOLUBLES      0.2    
WATER           0       
FLASHPOINT F   385    
SUS VIS 210F   43.4
cSt @ 212F     5.23
TBN             -
TAN             1.3


2017 Chevrolet Corvette Grand Sport
Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: dparm] #4530143
09/30/17 10:47 AM
09/30/17 10:47 AM
Joined: Jun 2002
Posts: 19,235
Iowegia - USA
MolaKule Offline
MolaKule  Offline
Joined: Jun 2002
Posts: 19,235
Iowegia - USA
If the fill was the 10 cSt Friction modified stuff, it sheared like crazy.

Do we know the GM or ACDelco part number of this fluid?

Last edited by MolaKule; 09/30/17 10:48 AM.

Reading is fundamental; understanding is not a given ability.
Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: dparm] #4530167
09/30/17 11:10 AM
09/30/17 11:10 AM
Joined: Jun 2002
Posts: 19,235
Iowegia - USA
MolaKule Offline
MolaKule  Offline
Joined: Jun 2002
Posts: 19,235
Iowegia - USA
According to the OM it's the ACDelco GM Fluid 88861800, which about 7.5 [email protected]

So it did shear but not too bad.

Last edited by MolaKule; 09/30/17 11:10 AM.

Reading is fundamental; understanding is not a given ability.
Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: MolaKule] #4531247
10/01/17 03:19 PM
10/01/17 03:19 PM
Joined: Apr 2010
Posts: 13,534
Chicago, IL
dparm Offline OP
dparm  Offline OP
Joined: Apr 2010
Posts: 13,534
Chicago, IL
Originally Posted By: MolaKule
According to the OM it's the ACDelco GM Fluid 88861800, which about 7.5 [email protected]

So it did shear but not too bad.



I'm going to stick with this change interval of "every 15 hours of track time" as it seems like that's a safe limit for this MTF, though I am definitely considering a more stout fluid -- any suggestions are welcome.


2017 Chevrolet Corvette Grand Sport
Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: dparm] #4531318
10/01/17 04:25 PM
10/01/17 04:25 PM
Joined: Apr 2010
Posts: 13,534
Chicago, IL
dparm Offline OP
dparm  Offline OP
Joined: Apr 2010
Posts: 13,534
Chicago, IL
Originally Posted By: dparm
Originally Posted By: MolaKule
According to the OM it's the ACDelco GM Fluid 88861800, which about 7.5 [email protected]

So it did shear but not too bad.



I'm going to stick with this change interval of "every 15 hours of track time" as it seems like that's a safe limit for this MTF, though I am definitely considering a more stout fluid -- any suggestions are welcome.



Hit the submit button too fast -- my short list includes Red Line D4 ATF and Renewable Lube's BioSyn XTRA ATF PLUS. I was actually surprised at Royal Purple's ATF spec sheet, too.


2017 Chevrolet Corvette Grand Sport
Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: dparm] #4533455
10/04/17 03:45 AM
10/04/17 03:45 AM
Joined: Sep 2015
Posts: 2,260
Malaysia
zeng Offline
zeng  Offline
Joined: Sep 2015
Posts: 2,260
Malaysia
Go for thicker oil, where track or otherwise.

Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: MolaKule] #4533456
10/04/17 03:46 AM
10/04/17 03:46 AM
Joined: Sep 2015
Posts: 2,260
Malaysia
zeng Offline
zeng  Offline
Joined: Sep 2015
Posts: 2,260
Malaysia
Originally Posted By: MolaKule
According to the OM it's the ACDelco GM Fluid 88861800, which about 7.5 [email protected].

So it did shear but not too bad.

Why aren't they call it ATF ?

Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: zeng] #4536255
10/07/17 02:38 PM
10/07/17 02:38 PM
Joined: Jun 2002
Posts: 19,235
Iowegia - USA
MolaKule Offline
MolaKule  Offline
Joined: Jun 2002
Posts: 19,235
Iowegia - USA
Originally Posted By: zeng
Originally Posted By: MolaKule
According to the OM it's the ACDelco GM Fluid 88861800, which about 7.5 [email protected].

So it did shear but not too bad.


Why aren't they call it ATF ?


Because it not ATF. Simply because it has the same viscosity as ATF doesn't mean it's an ATF.

A different additive package is applied to set of base oils to give you a 7.5 cSt fluid.


Reading is fundamental; understanding is not a given ability.
Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: dparm] #4537918
10/09/17 11:35 AM
10/09/17 11:35 AM
Joined: Sep 2015
Posts: 3,861
Connecticut
69GTX Offline
69GTX  Offline
Joined: Sep 2015
Posts: 3,861
Connecticut
Add package on GM MTL/ATF was typically 225-325 phos and 100+ boron. This one is weaker either from mfg or usage while driving (if possible). The drop to 5.2 cSt is similar to another Vette UOA that dropped to 5.0 cSt in 10,000 miles. I use the same stuff and change it out every 3-5 yrs at 3K-5K miles and no track use. 30% shear in 6K miles is a lot, though probably typical for a conventional "ATF-like" MTL.

Upgrading to a thicker solution with more additives (like a synchromex at 9 cSt) could have draw backs. The synchro's are designed to work at 6.8-7.6 cSt and the tiny needle bearings in the T56 benefit from that 7.5 cSt fluid. Pick your poison. Properly lubricate the synchros, bearings, or gears? It's typically hard to get all three, at least with the Tremecs.


----------------

2001 Lincoln Cont 4.6L DOHC/ 39K mi / QS HM 5w30 / FUG XG2
1999 Camaro SS M6 /19K /Mobil 1 0w40 /Fram UG /GM MTL-ATF
1969 Ply GTX/RRs
Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: dparm] #4538656
10/10/17 02:25 AM
10/10/17 02:25 AM
Joined: Sep 2015
Posts: 2,260
Malaysia
zeng Offline
zeng  Offline
Joined: Sep 2015
Posts: 2,260
Malaysia
With FE out of the windows in this application , this manual transmissions would really benefit from a traditional MTF that is thicker than a Synchromesh/ATF-MTF's barring ease of shift upon winter cold start.....
never mind OEM's recommendations.

Redline GL4 in MTL and MT85 should be considered for OP's ambients, though my ambients would favour a thicker one in MT90 .

I believe transmission roller and/or needle bearings loves higher operating viscosities in thicker oil, as are gears.

Re: 2017 Corvette / ACDelco MTF / 6.4k mi [Re: dparm] #4554695
10/25/17 10:59 PM
10/25/17 10:59 PM
Joined: Sep 2015
Posts: 3,861
Connecticut
69GTX Offline
69GTX  Offline
Joined: Sep 2015
Posts: 3,861
Connecticut
Just shifting to a full synthetic ATF will drop your shear rate in half or less (RL D4, Amsoil ATD, Mobil 1 ATF, etc.). I've heard lots of good stuff on the Amsoil ATD ATF. I'd be using that if I had a post-2000 Vette.

I recall a Chrysler ATF article that reported shear rates of 19%, 10% and 3% as you went from conventional, to syn blend, to full synthetic ATF.


----------------

2001 Lincoln Cont 4.6L DOHC/ 39K mi / QS HM 5w30 / FUG XG2
1999 Camaro SS M6 /19K /Mobil 1 0w40 /Fram UG /GM MTL-ATF
1969 Ply GTX/RRs

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