External trans cooler help

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Ricks70Duster340

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I want to install an external trans cooler while running the current bottom radiator cooler. The external cooler I have uses -an 6 fittings. I am pretty sure the radiator fittings are 1/8 NPT but not sure what the actual line fitting size is to get a fitting to make this happen. Thanks guys.
 

Anyone happen to know the size of the female fitting on the end of the metal cooler line that screws onto the lower radiator cooler? I will need that info to get a fitting to convert to -6 AN.
 
The 60-70's cooler lines are 5/16" flare. Sometime when they went to the A500/518 the cooler lines became 3/8 tube, with the std 3/8 flare to 1/8" mpt fittings at the trans.
 
The 60-70's cooler lines are 5/16" flare. Sometime when they went to the A500/518 the cooler lines became 3/8 tube, with the std 3/8 flare to 1/8" mpt fittings at the trans.
All the Mopar radiators I have added a cooler to have been 1/8”npt on the radiator side. Line size was either 5/16” or 3/8” or some sort of plastic connector (newer stuff)
Even though I run thru the cooler then the radiator’s cooler before returning back to the trans… many transmission guys I’ve used swear you donot have to do the “back to the radiator tank.” Before going back to the transmission. They told me that just having the cooler next to the radiator will warm up the fluid just fine. When I was a technician for GM, the schooling I took- the teachers said you can never keep a transmission too cold. But it’s easy to ever heat one.
Hope my info helps.
Syleng1
 
All the Mopar radiators I have added a cooler to have been 1/8”npt on the radiator side. Line size was either 5/16” or 3/8” or some sort of plastic connector (newer stuff)
Even though I run thru the cooler then the radiator’s cooler before returning back to the trans… many transmission guys I’ve used swear you donot have to do the “back to the radiator tank.” Before going back to the transmission. They told me that just having the cooler next to the radiator will warm up the fluid just fine. When I was a technician for GM, the schooling I took- the teachers said you can never keep a transmission too cold. But it’s easy to ever heat one.
Hope my info helps.
Syleng1
Normally the trans line runs to the radiator tank first, then goes to the external cooler before returning to the transmission. The only other way I've done it is to bypass the radiator completely and just used a large stacked plate cooler only.
 
Pics of your fitting bungs in question may help.....its hard to know what you have....the radiator will be 1/8 npt female as you said.....Aeroquip #6 is a decent equivalent line size, but i cant guess whats on the cooler....
 
You just do what you have to do. My cooler had barbs, so welded AN 6 fittings on. Still have a little more work to do.

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IMHO Get rid of the in radiator "cooler". It is completely unneeded with a stand alone cooler and avoids the eventual day when the 55 year old metal tubes in the bottom of your radiator gives up the ghost and coolant pressure pushes anti freeze into you trans. Have you ever seen a radiator shop replace those lines while recoring a radiator???
 
IMHO Get rid of the in radiator "cooler". It is completely unneeded with a stand alone cooler and avoids the eventual day when the 55 year old metal tubes in the bottom of your radiator gives up the ghost and coolant pressure pushes anti freeze into you trans. Have you ever seen a radiator shop replace those lines while recoring a radiator???
On most of my cars I *did* bypass the lower radiator cooler and go with a stand alone one. I am replacing my radiator with an aftermarket aluminum one so all will be new. The higher stall converter I will be installing will need good cooling so am installing another aftermarket one in series to be sure the trans stays cool. I live in South Texas, so it gets pretty hot here compared to where you live! Excess heat is not the friend for longevity in our cars!
 
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