I have a 1996 Powerstroke with the A4OD trans. When I take off, it doesn't seem to know what speed it wants to shift between first & second and then second to drive. It has done this twice in the last month. Drive & overdrive shift normally. The other day I took off from a stoplight, it shifted up to second & then back to first (engine shot up to 2000rpm) and after a little bit it shifted into second. All shifts are solid with no slippage. Almost sounds like a computer issue, but do not know much about this trans. Thoughts?