I have a 97 V6 5 spd also, as mentioned the 5th gear is an OD.

According to Allpar the V6 used a AS 82 transmission, 4th gear is 1:1 and 5th is .79 OD.

However, Most other reading would lead to believe it is an AX15. Definitely not the NV3500, which has the bell housing cast in smooth with the case, and appears to be V-8 only.