Which input shaft out of the np231 is longer? Is the input shaft that fits up to the AX-15 or the shaft that fits up to the nv3550 longer? Are they the same length?? I'm putting a Transfercase that was mated to a nv3550 tranny in my jeep with a Ax-15. just wanted to know if the input gear swap was necessary? thanks

Which input shaft out of the np231 is longer? Is the input shaft that fits up to the AX-15 or the shaft that fits up to the nv3550 longer? Are they the same length?? I'm putting a Transfercase that was mated to a nv3550 tranny in my jeep with a Ax-15. just wanted to know if the input gear swap was necessary? thanks
You shouldn't need to. Depending on which model np231 you have will determine input shaft, some are different, but they will all bolt up to the tranny the same. I've never done exactly what you're doing, but I've swapped plenty of 231's around and never ran into a problem.