I have a 2005 Dakota Laramie quad cab 4 X 4, 4.7L. Six weeks ago, I cold-started my truck. It started off in high gear. After if warmed up it was still in high gear, would not down shift. After cutting the engine off and restarting, the problem went away. It shifted normally until yesterday, same thing, from a cold start, my Dakota started off in high gear and would not down shift. I manually shifted it to low and second gear and that worked. After warming up the truck still would not shift gears. I pulled into the supermarket lot cut it off and went shopping for a few minutes. When I restarted the truck, it ran and shifted normally. Both times, the check engine light came on but I had no way of checking the codes. Any idea what this could be and estimated cost? It has 173+K miles on it. Many thanks!