50thz06

Hopefully not opening a huge debate here, but I want to change my trans fluid in my '03 Z06. I've read as much on the forum as I can find, except I'm not sold I know everything I need to know about the "paper versus non-paper" thing. I'm partial to Amsoil and would like to go with Amsoil. However, when I use the Amsoil website for their recommendations, their website pulls up nothing for Z06 trans, only the regular 6-speed for 2003. I know the GM rec is Dexron III, and Dexron VI is said to supersede Dexron III, so this should be easy, but if Amsoil doesn't have a recommendation on their own website for Z06, then what's up with that? Anyone have a definitive knowledge or should I just go back with GM Fluid? The car likely has GM fluid in it now, car was dead stock when I got it 18 months ago and had been parked for years. I've been busy with other upgrades and maintenance and haven't driven the car much since I got it. Yea, I can hear it now, "you should have changed all the fluids as soon as you got it." I hear ya..... Well, doing it now......

FR-CYA

From my own experience, the GM fluid was recommended and sold to me by Rick Kim at RKT Performance the day he completed a full rebuild of my T56. He's very well-respected in the Corvette community when it comes to transmissions. http://www.rktperformance.com
My car is a '99 FRC with a MN6, not a Z06 with the MN12. It had paper blocker rings until Rick installed carbon fiber ones, along with new synchros, gears, seals, bearings, shift forks, bronze keys, etc. I have over 1000 miles on it since the rebuild and it shifts like butter.

I wouldn't hesitate giving him a call if you have specific questions. He's a helluva nice guy too.

jackthelad

Dexron VI is a complete no-no for manual transmissions - GM issued bulletins pointing out that it may cause damage in manual transmissions. It only supercedes Dexron III in auto trannies.

All the C5 6 speeds need a fluid that meets the now discontinued Dexron III spec. As long as it does that, you are good to go. I've tried a few and Valvoline Dex Merc works as well as anything else, and is easy to find. GM makes one, as do the various
boutique brands like Amsoil.

Per GM:

"Dexron VI can be used in any proportion in past model vehicle equipped with a 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.

Dexron III must not be used in place of Dexron VI in models that specifically call for the use of Dexron VI, fluid and component life will be compromised.

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."

ArtClassShank

I went with the GM fluid (p/n 88861800) from a dealer when I filled mine. I'm almost positive every C5 after 2001 had carbon fiber blocker rings. Anyways, I swapped the fluid over 10K miles ago and I'm shifting fine.

2004 Z06

wscott62893

I run AMSOIL ATF and have for quite some time. I've never had any issues/ inconsistent shifting and noted a significantly smoother overall operation when I first made the switch. I know a lot of forum members use the same without any problems. That's what I suggest.

https://www.amsoil.com/shop/by-produ...?code=ATFQT-EA

Cutlassmaster

Just run the amsoil red cap auto trans fluid and you will be good. The blue cap is used for the dexron VI but red is for dexron III. I have put it in several and never had an issue and nothing but praise for how much better it shifts.

wscott62893

mmo24

This is the brand I'm going with when I change my tranny and diff fluid

https://www.redlineoil.com/find-products-for-my-vehicle

Bushman66

Running Redline in my 04Z, with the MGW shifter and the Anti-venom mod, it shifts as smooth as a baby's rear end. I've run Redline in every manual transmission car I've owned with excellent results.

walleyejack

i have an RPM transmission, and they recommend Mobil, Royal Purple and a few others. They told me they had the most issues with Red Line. i did the Royal Purple in trans and diff and added modifier in diff as they suggested even tho the bottle says it has it.
JM2pennies

QuickSilver_C5

I used Royal Purple all around, no issues, 15k Miles.

bwill03z

Not sure about the Amsoil but I just bought some Mobil 1 synthetic atf for my 03 Z06. Putting it in this weekend, I’ll report back on it. I was gonna go with the Redline D4 atf but they had the Mobil 1 at my local Autozone