88 K-5 Blazer transmission stops when it is hot???
 

I have a 88 k-5. My front drive shaft recently fell out. After the repairs to the drive shaft my transmission began acting up. I can drive it for 30 minutes to a few hours then all of a sudden it stops working as if the truck was in neutral. I can put the truck in 4x4 and it drives fine. I can allow the truck to cool off for a few minutes and the transmission will drive again in 2 wheel drive until it heats back up. I was told that it may be the transmission temperature sensor, but no one seems to know for sure. Has anyone else ever experienced this with the K-5s?
Thanks