Allison tranny cooler line size?

Squaremaxfan

New member
Mar 4, 2021
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I want to verify tranny cooler line size and I'm also wanting to install a dealer cooler in line w/electric fan mounted to it. The cooler is 3/8 line, will that work for the Allison cooler lines?

Thank in advance
 

Ron Nielson

Active member
Oct 11, 2009
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Berryton, KS
I'm pretty sure that the lines are larger than that, probably -10an (5/8"). I believe that someone posed a similar questin to Mike L about that a couple of years ago and he said that 3/8 wouldn't be enough flow and cautioned against restricting trans fluid flow in the cooling circuit..
 

2004LB7

Super Moderator
Staff member
Dec 15, 2010
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Norcal
I think it was 1/2" for the 5 speed and 5/8" on the 6 speed. and as Ron mentioned, restrictions are not good