2010 Corvette Manual Trans Dexron III 8,200 miles

[smonska]

Changed out my factory fill of Dexron III in my 10' Chevrolet Corvette Grand Sport. This car has a 6-speed manual Tremec TR-6060 trans with a trans cooler.

The car has seen a few street nights at the dragstrip and a track day at Lime Rock road course.

I refilled the trans witih Amsoil ATD , a "thick" dexron III equivalent with a cst of about 7.4. There was a significant difference for the better in shift quality after changing it, a cold "nibble" on 2nd/3rd was GONE! I understand why many on the corvette forums recommend the switch! I also added a magnetic fill plug while I was down there. I know there is a non-cleanable magnet inside the trans, but I like to be able to see how things are going.

 

[A_Harman]

That's horrible! Never mind what those guys at Blackstone say. You must immediately sell the car. It's completely ruined. I'll do you a favor and take it off your hands for $1000.

 

[Warstud]

Dexron III in a 2010 Corvette? Really!

 

[cchase]

It's a manual transmission, they spec Dex III.

 

[dnewton3]

ATD is Amsoil's top end ATF, meant for TES-295 applications; it is a premium clone fluid. I consider it a top choice for DEX/Merc applications, similar to 204S-AT, AutoTrans-5, etc and other clones.

That in mind, anyone notice that the vis has dropped well towards the bottom of the vis range in only 8k miles?

 

[Warstud]

Originally Posted By: cchase
It's a manual transmission, they spec Dex III.


I was wondering if that was why. Thanks!

 

[smonska]

To clarify, the fluid tested WAS NOT AMSOIL. It was the factory GM fill, I believe GM now classifies DEX III as "Manual Transmission Fluid" part number 88861800. It is supposed to be around a cSt of 7. It sheared pretty bad in a short time.

 

[A_Harman]

Gearboxes are great machines for shearing oils.

 

[dnewton3]

OK - I see now.


The UOA is on the GM "manual tranny and transfer case fluid" (formerly known as DEX III).

But You "refilled" with ATD, right? You'll be happy with ATD; very robust fluid.

 

[Bror Jace]

Didn't want to try a GL-4 fluid like Honda MTF II or Royal Purple Syncromax?

 

[dailydriver]

Originally Posted By: A_Harman
Gearboxes are great machines for shearing oils.


Yes, I have noticed this about the T56es/TR6060s especially.

Mine seems to shear even Red Line MTL VERY quickly, not by any UOA, but by how short a time it takes for it to start whining again after a fresh change (when it was almost silent immediately after said change).

Next time, I might just use 2 quarts of MT85, or even one quart of the MT85 and one quart of the MT90, to go along with the other 2 quarts of MTL, cold weather start out shifting be d****d.

 

[dailydriver]

Originally Posted By: Bror Jace
Didn't want to try a GL-4 fluid like Honda MTF II or Royal Purple Syncromax?


Some (like myself) have had VERY VERY BAD experiences with RP Synchromax in the Tremec 6 speed boxes.

It ground EVERY gear sooo badly at EVERY shift (fast OR slow), that I thought it would kill my synchros/blocker rings witin a half hour of driving.

I dumped it the same day I installed it, despite losing the ~$75.00 I paid for the stuff.

My guess is that their 'Synerlec' additive is just way too 'slippery' ) for the Tremec blocker rings.

 

[Bror Jace]

Wow dailydriver. I'm really surprised to hear that. I am not fan of the purple stuff, but I thought it was specifically developed for the manual transmissions used by the Corvette and F-bodies (previous generation Camaro and Firebird) that call for an ATF thin fluid.

Good to know.