6l80 Transmission Cooler Flow Direction
The transmission fluid low of the 6l80 goes as follows:
- Bottom line leaving the transmission to lower radiator port
- Lower radiator to upper radiator port out to external transmission cooler
- External transmission cooler to upper transmission cooler line port
If you do not have an external transmission cooler, the cooler line flow goes as follows: lower cooler line > lower radiator port > upper radiator port > back to upper transmission line.
After 15+ years in the automotive industry, I’ve developed strong opinions about transmission cooling — and about the lack of reliable information available to enthusiasts who actually need it.
I’ve built and developed transmission cooler systems across a wide range of applications: street cars, race cars, and trucks. I created this site to put what I know in one place.
If you’re an automotive enthusiast trying to make a smart decision about your transmission and its cooling needs, this is the resource I wish had existed when I was starting out.
