ATF cooling: Is the radiator enough?

[Kern Dog]

Since I swapped from the 318 to the 440, I have used an external ATF cooler. Currently I have a 1970 Charger with a 440/493 and a Griffin radiator without an internal cooler.
I am converting to A/C and part of the project includes a radiator swap. The new radiator has a cooler built in but I am wondering if it is enough. I do not drag race the car, I run on the street mainly but do plan to run it on a road course in the future. I have considered running the ATF lines to allow the fluid to pass through the external cooler as well as the radiator. If I do this, should it be routed so that the fluid passes through the radiator first? Which line on the trans is the discharge and which is the return line?
Thanks.

[c00nhunterjoe]

Front fitting is outlet. Rear is return. I would run both coolers on a street car. Put your gauge at the outlet line for the most accurate reading.

[Kern Dog]

Thank you. All of these years and I never knew that !

[c00nhunterjoe]

I remember the oddest things sometimes, but yet forget why i walked in the kitchen.

[Kern Dog]

Me too. I remember phone numbers, addresses, VINs from cars I owned, license plates, dates too. I forget people names too often though. 

[c00nhunterjoe]

Name tags.

[John_Kunkel]

Put your gauge at the outlet line for the most accurate reading.

Depends on your definition of "accurate". The outlet is likely the highest temperature the fluid will achieve but the temperature of the fluid in the sump is a more practical measurement IMO.

[c00nhunterjoe]

I prefer to know the output temp, so i know how hot my converter is getting.

[Derwud]

When it comes to an automatic trans, COOLER is better..

[alfaitalia]

Hmmm...looking at that chart..are they really saying that a 20 degree drop from 195 to 175 will double the life of the tranny? Seems unlikely........maybe I'm wrong.

[Kern Dog]

Well, from 800 miles at 315 degrees to 1500 miles at 295, that is almost double!

[Bronzedodge]

KD, is your converter stock or aftermarket?  Cooler is better.  There is a diagram in the Mopar Chassis book that shows the tube routing for the radiator and auxiliary cooler.

[Kern Dog]

The converter is an aftermarket 11" unit built to order by Lenny at Ultimate Converter Concepts. It drives as if it has nearly no slippage. I did have a crappy one in  the car for awhile. THAT turd slipped as if I were low on ATF.

[DAY CLONA]

I'm mostly a manual transmission guy, but still occasional play with automatics....


The factory cooler located in the radiator was intended for a 2 fold operation, warm the trans fluid for initial/cold start operation and fluid warming in winter time usage, as well as maintaining a somewhat "cool" running temp during operation in all seasons

Some schools of thought are to run the factory cooler to prevent cold fluid operation of the tranny, some use the factory cooler and an aftermarket cooler in series, some run just a remote cooler...some frown upon a remote cooler citing short transmission life due to lower running temps, IMO that may apply to stock configurations only

Personally I've opted in most cases to run a remote cooler and forego the factory cooler , most of my reasons were that I was running a full manual valve body on the street as well as some loose torque converters, and at one time a clutchflite auto, all which can generate some additional heat

I've also found out the hard way some factory coolers located in the radiator can't handle high line pressure, I lost a tranny as well as other individuals I know by having the factory cooler burst/crack mixing water/coolant in the tranny, you usually find out the hard way with pink foam frothing out the dip stick or tailshaft seal, or a pink flume of under hood overheated vapor as your radiator cap blows off... by then the trannys junk

I vote, remote

[John_Kunkel]

and at one time a clutchflite auto, all which can generate some additional heat

Huh? A Clutchflite generates additional heat?

[68CoronetRT]

I run an external cooler only and have the sender before it hits the cooler. I usually see around 210-220 when I romp on it, so I know that I'm good since that will be the hottest reading.

[Kern Dog]

That is interesting. I have not seen a car with a transmission temperature gauge.