i have a 99 ranger 4x4 auto that i just got done with a 3.0 to 4.0ohv swap on ....everything went well with the swap ...i changed tranny bellhousing and bolted the 4.0 to the 3.0 tranny ...the guy that had the truck before me had put a 96 3.0 in the truck and had changed alot of junk that i know nothing about and said after he did that swap it would no longer shift into overdrive ...well since my swap it wont shift into od either i know the guy well and he says it was shifting fine before his swap but never shifted into overdrive after ....the od light is flashing and codes say range sensor high output ....changed range sensor with no change at all....i have no clue at all what to check next so any info would be great .....the 4.0 is running off of the 3.0 emc and runs fine except for and occasional miss at idle that i cant figure out but also does it with the 4.0 computer but tranny wont work at all with the 4.0 emc ...any help on the occasional miss would be great too have changed pluggs wires and coil packs....thanks for any info 
