I'm installing a separate transmission cooler on a 2001 savanna van. Which of the two cooler lines( top or bottom) into the radiator is the return line?
Transmission is not in the van.
Thanks
Ron

 

The one that's cooler to the touch :P

 

you haven't posted enough info...do you have a 1500, 2500 or 3500? they have different transmissions..

 

I have the 2500 series with the 4L60-E transmission. Are the lines plumbed differently in the 4L80-e transmission?

 

As stated in the original posting, the transmission is not in the van. I'm plumbing the transmission cooler in advance of the new tranny going in.
Both pipes are dangling under the van. Both feel the same at this point.

 

4L60e pressure/outlet is the lower port, it would go to the upper connection on the radiator.
4l80e pressure/outlet is the front port.

 

> Both feel the same at this point.

I'm just kidding.

 

The top one should be the return line. Plumb your cooler in there.

 

Looked in the GM Service manual and they have the additional transmission cooler plumbed from the bottom line for the 4L60-E transmission.

 

I've seen that diagram too. It's wrong.