2002 vs 2003 allison.

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,065
4,736
113
Phoenix Az
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?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,686
232
63
Fullerton CA
'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

Vendor
Vendor/Sponsor
Feb 1, 2018
3,895
1,067
113
Neenah, Wisconsin
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.
 
Last edited: