I'm a rural mail carrier and the problem is causing a big problem. After the transmission was rebuilt , it worked for a while, then started the same thing again. It might do really good most of the day, then in the afternoon,when I stop to deliver a package or certified to the door, I start the engine up,backup, then try to put it in drive, and it acts like it is in neutral. I try all gears and nothing happens. By the time my husband gets there it might work as if nothing is wrong. The guy that rebuilt the transmission is baffled as to what is wrong. I need help.