Anybody knows a vendor that sells one with 1/2 inch fittings? Our 1st Gen trucks have 1/2 inch lines and fittings only to be restricted by aftermarket "HD performance coolers" with 5/16 or 3/8 fittings.

 

You're very smart to consider only the ones with 1/2" fittings. I've seen them at summit.com, which means jegs.com probably also has them. There are probably other places that have them cheaper, and you could also probably find them on Ebay too. Yech, I feel dirty recommending Ebay...

 

In further researching this, I found them and decided on a Tru Cool Industrial cooler, 11x11 with 1/2 in. fittings, with 29K BTU capacity, for $68. I also found even higher capacity ones for Allison industrial coolers with 3/4 inch and even 1 inch fittings!

 

Not cheap, but B&M has a line of SuperCooler Oil Transmission Cooler w/ a 12v fan w/ 1/2" NPT Female Ports.

My temps seem to go up only when I'm at slow speeds, traffic, backing and the like where an just an additional cooler without airflow doesn't help too much... just a thought.

 

Mine is a Derale with a thermostatic controlled fan. And as was said above, it is mostly for bumper to bumper traffic.

 

You want to try and get one that is "Fin and Plate" design, this is what the factory optional under bed cooler is, and is more efficient.

Also while you are at it you should install a spin on filter in the cooler circuit to catch the clutch and other particles in the fluid.

Jim