Hello i am turning my 1999 express van into a 4x4. I am useing a set of running gear off off a 1980 3/4 ton chevy truck. What i want to know is will the 1980 trany bolt onto the 1999 4.3 engine. Or is there a way to modify the auto trany that is already in the van to take a 1980 alum transfer case. Any other ides will be great.