So I just recently did a head gasket on my 2010 4.0, and I think working around the radiator and pushing up against it accidentally has caused a transmission fluid leak from the driver side at the lower connection that I believe goes to the transmission cooler. My truck does have the tow package so it does have the transmission cooler.

so my question is, does anyone know what that part is? I can’t even find it on rock auto. Additionally, does anyone know the thread pitch and diameter? Hopefully I can do something janky for free or cheap.

 

So you think you cracked an old and fragile cooling line?
Clean the area thoroughly. Have someone start the vehicle while you're right there looking for the leak's source.
I believe anything tubing related is a relatively standard fix.

How many miles are on your 2010?
What made you do a head gasket?

 

I definitely know it’s leaking from the line, I see it dripping out from it when it’s all warmed up. I just can’t find the part from any brand except FOMOCO and I would like to see if anyone else has made the line.

i have about 195k miles on it, and I just replaced the water pump on it recently, and I think that played a role in blowing the head gasket. I hammered down on the gas a little bit because I was seeing if my shifting issues were fixed (seems like they were) and in the process my front passenger cylinder ( I believe cylinder one ) started pissing out coolant into the center crevasse of the block where the knock sensor is.

im just hoping I could cut the metal line back and find a new fitting to pop into the radiator, and put a rubber hose connecting the 2 metal lines if I could

 

I've seen repair kits for fuel lines at NAPA stores, but not for trannie cooling lines.
I think this is because the parts are very standardized.

Try here: Merchant Automotive Transmission Cooler Line Repair Kits | Thoroughbred Diesel

Or this: Transmission Cooler Lines | Replacements and Repair Kits

This one is interesting: TRANSMISSION OIL COOLER LINE REPAIR KIT FOR 5/16" & 3/8" LINES WITH 80pcs & 15' OF HOSE - Transmission Parts Distributors

There comes an age for vehicles where the "Don't patch, replace it all", rule comes into play.
I'd think cooling lines are like brake lines, they can take the stuff off a roll and terminate however they wnat.