97 4x4 with 4.3 and 4l60e. 3rd gear is neutral on occasion. If I let it shift on its own it just revs in 3rd. If I floor it I can get it to grab in 3rd and then its fine until I come to a stop. If I shift manually from first on up 3rd will usually work like it should. 4th gear is fine. No codes. I was hoping for an easy fix but its a 4l60e so I'm looking for a trans.