Transmission only works in 1st and R until engine warms to 180 Then is fine???

Trans was having probs with hard shift to 2nd then got worse and only had 1st and R. Also would be driving and car would stall for no reason. Now whe car watms to 180 trans runs fine. Got new batt. starter and alt. Check fluids all are at right levels. Was going to have valve body replaced as previous advised. Not sure what to do now with this developement.???