UGgHHH !
I've personally been down this road before with the same year Jeep. My older brother had a CJ ,and when it came time to change the oil in the T-5 it was very confusing as the original owner put in gear oil because his " mechanic" buddy told him to do it. The owners manual we had said to use a special oil sold from AMC. That oil was discontinued a long time ago. I believe it was 1983 that there was a change from AMC to go from gear oil to ATF and that's why there is so much confusion. I think it was the change in blocking rings to a fiber type from brass.
We put in ATF ( Dextron 3 or Mercon) and finally switched to Redline synthetic ATF when it became available . The CJ still has the original tranny and my brother has been using ATF since 1989. No grinding or noises and it's well over 300 000km.