i had parked my blazer for about a year since i bought a truck and the fuel pump went out on the blazer. didn't feel like paying 400 for a new pump/sending unit assembly. found a pump only for 40 and bought it, changed it and started up ran fine. while it sat it developed a leak at the pan during the winter. i have a new filter/gasket for it however even after refilling it to the line and running it through the gears and rechecking just to make sure it will not pull its self in any gear it will move a little around 2500 rpm but i don't want to burn it out so that was a one time thing. no burnt smells, sounds any otherwise. just won't take off. i've scanned it and no codes found. anyone have any ideas for when i pull the cross member and pan to change the filter on what to inspect. and yes it was doing fine until it sat for a year.

 

Sounds like either the torque converter is not operating properly or the pump is broken. If the torque converter has been completely drained, it may take a bit of idle time for it to fill back up.

You didn't have any reason to pull the torque converter to flex plate bolts did you?