My 96 service manual show 3 transmissions 42re,46re and 47re.
I would think that the 42re is for 1500's, that the 46re were in gas 2500's/3500's and we know that the 47re is used for diesels 2500's/3500's.
I don't recall if there was a 360 heavy duty in 2500's/3500's but I think there was.