i have a 96 chevy 3500 6.5 idi with a nv 4500 trans i would like to convert it to my 96 5.9 12v motor will the trans i have work? or do i have to change the main shaft? and if ne one has done this b4 please lmk if there is ne thing i should look out for

 

Kinda. You would have to change the input shaft to use a Dodge clutch, but thats only if you have the same ratios in the trans. Other than that, the bolt pattern for the bellhousing is different. IIRC you have to drill 2 holes in the bottom of the trans for bellhousing, should be an "ear" cast into trans case. Think thats about it.