Why did you swap fans? The 13870 is what I have mounted under the passenger side of the cab outside the frame rail and it keeps my trans cool. You can see it in this picture when I was building the H-pipe.Here is the cooler I have but without the fan.
It should be more than enough but it isn’t.
https://derale.com/product-footer/f...rs/hyper-cool/hyper-cool-extreme/13870-detail
The fan I have on it is this one from my previous cooler.
https://derale.com/product-footer/f...unt2013-10-28-09-53-271226240719/15900-detail
The fan is a puller, so it's sucking cool air up by the ground and blowing it out the top.
" trans, and I had to baby it when I put the stocker back in. Was a 14.1 with the old motor which was essentially an iron block LS3 with a mid size cam in it.


