Why would a 2004 Nissan Maxima with a recently remanufactured transmission be having 4th gear issues?

I took my '04 Nissan Maxima 5 spd auto (RE5F22A) to my mechanic and had my transmission replaced with a reman unit. After the install, the car was driven by the technician and noticed that the gears were not smooth but hesitated into gear. After additional research, he was told by the shop that remanufactured the trans that the TCM may need to be reprogrammed to work with the new trans. After having that done by Nissan, I was told the car had been driven and is ready for pick up. I drove the car for about 10 minutes...seemed fine. Then after a red light, the car went through 1-2-3 then 4th was like it went into neutral??? no power while in high gear. Tried to autoshift but no such luck. Test drove the car a few times but it seems like 4th gear is gone...rpms revs. What else should I have looked at. Trans plus labor cost me $4K...