Grinding noise on startup

#1
It's an 05 automatic with 165,000km/100,000 miles. When I start it up for the first time that day, and its especially prevalent when its cold, I get a grinding noise. Its especially bad when i accelerate but it will stop after about 5 or 10 minutes.
I thought it was the transmission at first but it only happens when its getting "warmed up" and the fluid is still good. Maybe the starter? There is a video of the grinding/groaning sound it makes.

 
Top