AFAIK, the NSS has nothing to do with shifting the AW4. It's purpose in life is to prevent you from starting in any other gear besides N or P, provide a circuit for the backup lights, and provide a continuity ground to the ECU to allow starting. Once started, the NSS is out of the TCU circuits and tranny solenoids that control shifting. You can pull the NSS and clean it, can't hurt, but first, since it's been sitting for awhile, I would drain the tranny, change the filter, and add about four quarts of fresh ATF. Especially if it's not been done in awhile.
i changed it last summer