Transmission feels like it's stuck in gear
 

I have an 05 Dakota Laramie package 4.7L 4x4 automatic. Today i was leaving work backed out of the spot just fine, put it in drive and the truck felt like I was pulling a heavy load. Kinda felt like it would if you was to pull away from a traffic light in second or third gear in a manual! I couldn't feel it shift like i normally could. I was rolling 60 mph at 2500 rpm. I pulled over and unhooked the battery. Hooked it back up and it was fine. Stopped to get gas and it did it again. Shut it off and back on again and it was fine. Fluid is right where it should be. Any ideas what would be causing this?? Thanks in advance!!

Had it scanned for codes?

sounds like it needs a good flushing and filters, also check that the solenoid pack is not on its way out