Allison 5sp: What trans fluid

[2003 duramax]

What trans fluid should I run in my Allison. I'm rebuilding with a ppe stage 5. Also I can get royal purple for real cheap. Is there anything I can run that they have. thanks.

 

[paint94979]

What trans fluid should I run in my Allison. I'm rebuilding with a ppe stage 5. Also I can get royal purple for real cheap. Is there anything I can run that they have. thanks.

Dex III or Transynd... Dex III is what i run in my trans

 

[2003 duramax]

Is it just dexron III , plain old trans fluid or are y'all running synthetic. Also what make.

 

[calabria69]

Just plain ol dexron III....

 

[Dmaxbandit]

What brand DEX III do you use? I need to change mine and am trying to determine what will be good.

 

[calabria69]

Any brand....I use the cheap stuff, been using it for three years, no issues at all...

 

[TrentNell]

I just use the Napa Dex III stuff , its never given me an issue ,and the price is right too

 

[Subman]

FWIW some builders feel you should use Dex III and not the synthetic stuff due to it being too slick and doesn't perform as well in a built tranny. I know the GM specs call for the synthetic stuff in the 6 speed but if you build it better to use the Dex III or so I've been told.

 

[UPS DRVR]

I use Castrol dex III no problems

 

[Dmaxbandit]

Thanks for the input! I was planning on using plain ol DEX III, but was always reading about transynd & really did not want to pay that much for trans fluid. Again thanks!