Transmission cooling lines in new aluminum radiator

[JohnnyPopper]

In replacing my radiator, I noticed the tank fittings were 1/2 inch instead of 5/8, looking inside, the opening was roughly 1/4 inch diameter.

I called the distributor, was told not to worry, aluminum is more efficient at cooling. So much for a 'factory fit' replacement.

The transmission is a '66 GM THD 425, and the cooling lines are definitely a higher capacity.

I thought I could laser measure the temp after a run to see if the trans is running hotter then the engine by a significant percentage.

Being ignorant of transmission design, I don't know if this obvious restriction is severe, or if the 'flow volume' of oil is not that great.

It's not that there are load issues.

The question is: should I worry? and/or add an outboard cooler, bypassing the wimpy one?

As always, thanks in advance for you help!

 

[Shifty]

A lot of folks will say "run both!" plumb from one to another...I don't subscribe to that theory.  I much prefer the solo cooler, as big as you can fit.  JMHO.

[JohnnyPopper]

Thanks Shifty..need to see how much real estate I have that's accessible. Pretty packed in there.

Thought about calling manufacturer again to ask if they have a volume rating.

[ehjorten]

I have always run from the transmission, to the external cooler, back into the radiator cooler, then back into the transmission. I have this on all of my automatic vehicles and have never had an issue in 30 years. I do think however, that it might matter in what climates you are running your vehicles. If you run in cold climates it might help to warm the fluid up a bit before you dump it back into your transmission. That is the theory anyways. I have never tested it with actual transmission temp gauges. There are aftermarket thermostatic control valves that will bypass the cooler until the fluid reaches a certain temperature. Derale and Improved Racing make them, I know.

[Shifty]

Being in AZ, that's never been a consideration for me...I get a choice, hot, or hotter.

[Captkaos]

if running inline I always run trans to rad cooler, then to rad to external if you can mount it at the front.
GM ran all of them that way when they did HD trans cooler. 
I am currently rerunning my Turbo truck remote as there is no room at the front with the Rad, AC and Intercooler. (pics will be posted)

[VileZambonie]

Buy yourself them there braided trans cooler lines. You can loop em any which way you need to and they're cheap $$$