My father just bought a 97 K2500 with the auto tranny. When you first start down the road it doesn't want to go into overdrive. After a couple of miles... say 5 or so it will eventually fall into it, then it does fine. Any suggestions?

dose it do it when the truck is cold or when its warm/just been driven also? I know when I had my 96 6.5 it wouldn't go into OD until the motor was warmed up..

Also, I think OBD2 did this and OBD1 dose not (at least on my 94 it doesn't)

the truck wont go into overdrive until the tranny is warmed up some. Completely normal.