I wonder if the function of the external bypass depends on the type of fluid used. Ex dex III is more viscous than dex VI so I wonder if the temp at which the fluid flows through the bypass is different with the different fluids.

 

GM transmissions call for the DEX/MERC III i think.
Supposedly "built" transmissions aren't supposed to use synthetic fluid either.

Don't quote me

 

DexVI is backwards compatable with Dex III.

So you can use Dex VI in applications that call for Dex III (except the T56). You cannot use Dex III in an application that calls for Dex VI.

The dex VI is a somewhat less viscous (thinner) fluid than the Dex III.

 

There ya go

 

^ PS sorry I quoted you.

 

Its all good. I knew there was a comparable fluid out these days. Just didnt know which one.

 

Well ive put some miles on her today and i havent seen the trans temps get above 150 yet
On the highway cruising im seeing 130*. So since the uninstall of the thermal bypass i have managed to drop about 40-50* on the fluid temps. Im happy

 

Having the same issue with my tahoe...circle D 2600 30k trucool with bypass...seeing temps of 180-190 in 90 degree F ambient temps. I dislike how it "fully" opens at 180...IMO it should be lower. This past winter with a 6-7k trailer in tow I was seeing temps. up to 220, granted they would recover nicely with the larger cooler, I just think that with the bypass it keep my trans temp about 40 degrees hotter than usual. Pulling the pos bypass asap.

 

Good info guys.... I am not a fan of the bypass, but I live in Texas. I guess it may be necessary in some places, but fully open at 180 seems scary. If it was fully open at 120 then maybe.

Chris

 

Yep i dropped about 30-40 deg without the bypass. The trans and converter feel much better staying cooler