Transmission Cooler Lines

Greg C.

Active member
Oct 11, 2019
256
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Well, I finally got to the task of pulling my radiator yesterday. Radiator is out, bracket has been cut, and bolt on mounts will be welded on in days
to come.

Radiator has such pretty Statue of Liberty green streaks on it, although I never saw it leak. Fins near the bottom are beat up pretty badly. I plan to
have it re-cored and install a lower guard.

I got all the lines loose except one transmission cooler line, which was rusted so badly I just went ahead and twisted it in two to get it removed.
Since I now need new cooler lines, is there any advantage to

going with the 3/8" diameter lines? I know the larger line flows more volume, but I didn't know if the factory cooler would be able to increase the
amount of heat removed with the larger flow. I think Jim K

may have cooler lines for a 403, or I can make my own. What is everyone's recommendation on going with the larger lines? Or is a waste of time and
effort?

Second question. After pulling the radiator, trans fluid was still leaking from the cooler line. I put a pan under it and quit for the evening. Today,
I was surprised to see two or three quarts of fluid in

the pan. Did I manage to accidentally partially drain the converter?

--
Greg Crawford
KM4ZCR
Knoxville, TN

"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
 
THM-425 guru Manny Travao recommends upgrading to 3/8th inch lines for better cooling.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Larry: Thanks for that link. It was most helpful. Jim, obviously GM thought it was worthwhile if the 3/8" lines were included in the tow package.

I will be contacting you for the transmission cooler lines, and oil cooler lines.

Are the transmission cooler lines pre-bent for the 403, or do I have to fit them?

--
Greg Crawford
KM4ZCR
Knoxville, TN

"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
 
Manny replaced my insulated cooling lines (recently replaced) on the street side of the engine with custom-bent (by Manny) brake lines that went over
the top of the transmission to the (cooler) curb-side of the engine and to the radiator when he rebuilt my transmission. Don't know the diameter -
ask Manny.
--
Darryl Meyers

1978 Eleganza II

El Dorado Hills, CA