Normally If the truck is shifting fine until the light begines to flash and only a little more of a bump when it shifts after it starts you are experiencing high line pressure due to a safety mechinism in the trans you problem is a stuck or faulty torque convertor clutch soleniod switch 150.00 - 250.00 depending on where you go to fix it and the parts supplier they use takes maybe an hour. most of you all getting those rebuilds are just being taken to the wood shed by the trans shops.