I have a 2005 Chevy Tahoe 2wd with the 4800 Vortec and what I think is the 4L60E transmission. When I shift into D from park it just shutters or pulses and the truck does not move for about 10 seconds, it will then take off stumbling the whole time. If I go from P to 3, 2, or 1 it takes off (accelerates) fine. I can then shift back to D and everything is fine. I can come to a complete stop and as long as I don't move the shifter it will take off as normal. I can floor it and it will shift through all the gears as normal. Is the transmission toast? Is this an electrical problem?

Thanks,
Ryan