I have a 2002 extra cab P/U with the 4.8 2 wheel drive.
sometimes after a hard stop(light change ,have to hit breaks hard and fast but not activating ABS,not that hard).When I start off it seems like the transmission is in 4 gear.The truck starts to move as the transmission downshift,I can feel it,than gets to first,this all happens in about3-5 seconds.than the truck is fine for weeks or months.
It doen't do it all the time maybe 1 time in 50 harder stops(1 to 2 times a month).
The transmission is not slipping it just doesn't downshift from the higher gear till I start taking off.

Any Idea's what is causing this?

 

possibly the shift solenoids. there are two. one for the 1-2 shift, and one for the 3-4 shift. they are in the transmission. you will have to drop the pan. i would find a good shop to plug into computer, see if they can tell exactly what's goin on.

 

Thanks,I get no lights and it only happens once in a great while.Does the computer store that kind of info whitout a light coming on?
I ask because it would be hard to repeat the problem unless I left my truck with them for a month.