2002 vs 2003 allison.

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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yes, just swap over the cooler line fittings in the bellhousing from the trans you pull to the trans going in.
 

Mike L.

Got Sheep?
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Aug 12, 2006
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'03 was a change over as far as the cooler fittings. Early '03 used the 3/4 by16 fittings ( same as '01/'02 ) and the late '03 used the 7/8 by16 fittings which are the same as '04 through '19. Adapter fittings are available to make either one work.
 

Bdsankey

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Feb 1, 2018
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I did not say swap the fittings.
You know what I meant Mike, the fittings need to be swapped on the 03 trans to the GM adapter fittings if it's a late trans. If the trans is an early 03 then it's a cake walk with zero work required.
 
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