Transmission Fluid

[Gorgon]

Does anyone know if they are still filling the C5 manual transmissions with Dexron from the factory? My local Corvette specialist changes the cars he works on to GM's Synchromesh synthetic trans fluid. My FRC was shifting pretty hard and I changed the fluid last night and it made a world of difference. I'm just curious of GM had started using Synchromesh from the factory yet or not.

Leon

 

[Gorgon]

Talked to local dealer and theie Corvette tech said they still get Dexron at the factory.

Leon

 

[c4c5specialist]

Hi there,
NEVER PUT SYNCROMESH in a T56 transmission.
Dexron 3 is what is recommended, and this is what should be in it.
Allthebest, c4c5

 

[Gorgon]

What is the Synchromesh's recommended use then? It is a synthetic tranmission fluid by GM. What vehicles are slated to use this fluid? What damage will it do to my transmission by using it?

Leon

 

[c4c5specialist]

Hi there,
Syncromesh transmission fluid is used in many manual transmissions, NV1500,3500,4500 in GM S/T and C/K trucks. Getrag/Isuzu 5T30 in front drive N/L/J cars. Tremec T-5 in older F cars.
However, the syncronizers within Corvette are engineered to work correctly with Dexron 3 in the T56, not syncromesh.
You can expect that with extended use, you will find increased bearing wear, and syncronizer blocker ring wear, as well as the friction cone surfaces.
Allthebest, c4c5

 

[Gorgon]

Thanks for the info. I will look at moving back to the Dexron.

Leon

 

[Mr.Cool]

C4C5
Will the same wear issue apply with the use of Red Line D4 in the C5 manual transmission?

Tom

 

[c4c5specialist]

Hi there,
No, Redline D4 ATF is still a Dexron 3 automatic transmission fluid. This will NOT accelerate wear within the transmission, the way Syncromesh will.
However, D4 will slow down the spin time of the syncronizer, due to a higher coefficient of friction.
This is why Redline usually helps the notchy actions that are sometimes felt with T56.
Allthebest, c4c5

 

[webxfx]

I'm guessing that GM's new Dexron VI is ok?

 

[cigar38usa]

Mobil 1 Synthetic for trans ?

I have read many good things about Red Line D4 ATF for the 6 speed in the 99 FRC. How does Mobil 1 synthetic stack up ?

 

[Glide]

Hi there,
Syncromesh transmission fluid is used in many manual transmissions, NV1500,3500,4500 in GM S/T and C/K trucks. Getrag/Isuzu 5T30 in front drive N/L/J cars. Tremec T-5 in older F cars.
However, the syncronizers within Corvette are engineered to work correctly with Dexron 3 in the T56, not syncromesh.
You can expect that with extended use, you will find increased bearing wear, and syncronizer blocker ring wear, as well as the friction cone surfaces.
Allthebest, c4c5

I'm confused. Will synchomax do good or harm in my 6sd 99 FRC. Lots of people reccomend it. How much is required for a drain and refill?

 

[mqqn]

Hi glide -

You are talking about using gear oil in a trans desiged for low-viscosity ATF.

Just asking for trouble there.

Use Dexron III or equivalent ATF. It takes ~three quarts.

best regards -

mqqn

 

[minifridge1138]

I have been told (but not confirmed) that Dexron VI is backwards compatible with Dexron 3, but not the other way around.

So i would guess (JUST GUESSING) that you could use Dexron VI.

 

[mqqn]

I have been told (but not confirmed) that Dexron VI is backwards compatible with Dexron 3, but not the other way around.

So i would guess (JUST GUESSING) that you could use Dexron VI.

Hi minifridge1138 -

That is correct, as this is just an enhanced formula of the Dexron III, and it retains the viscosity characteristics of the original.

best regards -

mqqn

 

[c4c5specialist]

Hi there,
No, GM DEXRON 6 is NOT compatible in a MANUAL TRANSMISSION application, ONLY AUTOMATICS.
88861800 is for use in manuals.
You can refer to GM TSB 04.07.30.037D, which states:

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.

Allthebest, c4c5

 

[mqqn]

Hi c4c5 -

My mistake - I thought it was Dexron 4 - wasn't there a change and the factory started using something else in the C6 manuals?

best regards -

mqqn

 

[c4c5specialist]

HI there,
No, it was either Dexron 3 or 88861800.
Allthebest, c4c5

 

[Gry Ghst]

How do you put fluid in a 2004 automatic?

 

[Glide]

How do you put fluid in a 2004 automatic?

Put it in the dipstick hole

 

[Gry Ghst]

Put it in the dipstick hole

There isn't one on a 2004.