In the morning the overdrive light flashes on and off rapidly. Very sluggish when first going. Sometimes it doesn't want to shift into overdrive. I pull over and turn off 2000 Xterra. Restart and it shifts fine. With it being sluggish in the morning I always manually shift from first to drive. Seems to help a little. Thanks for any advice. Have had it into the two different shop with no luck as to why. They don't think it's the transmission.