Bus with a T444e need tranny change.

[OLDBULL8]

I know a guy who has a school bus with a Navister T444e engine (same as a 7.3 PSD) that has an AT545 or an MT643 tranny in it, tranny is only a 4 speed 1:1. Will a 4R100 hookup to it? He wants an OD tranny. Anyone know? Please PM me, don't look at this forum often and might forget about it.

Edit: The Allison has a SAE2 bell housing if that helps.