Shifting problem 300zx 90

[reinvention18]

1990 300zx. Car shifts from 1st to 2nd in automatic like a dream. after that it goes all the way up to over 5k rpm before it will shift to 3rd and i more or less have to floor it to get it to shift. Checked the TCM and i believe bored looks good, I can upload pictures if needed. Check wiring and it looks good as well. This is a new transmission as well started happening about 2 months after it was put in. Issue was intermittent where sometimes when i would drive it, it would shift fine and next day had issues shifting and next day fine. Its consistent now. Any ideas would be greatly appreciated thanks.