The sensors on the valve body (inside the trans) are different. You will need to switch them.
No
No.
No
nono
No.
Put the van on the lift and drain the transmission fluid, next drop the transmission on a tranny jack and proceed to do a transmission overhaul. Reverse the proceedure to install.
Same engine? If so then yes.
A 2004 Ram 1500 has a 45rfe transmission.
no
2000
No
1994-2001 Dodge ram 1500's have 5.5 on 5 bolt patterns. 1994-2002 Dodge Ram 2500/3500's have 6.5 on 8 bolt patterns.