Ford Repair: SLIPPING TRANSMISSION, 1999 ford windstar, ford windstar

Question
1999 FORD WINDSTAR,3.8L,O/D TRANSMISSION.
PROBLEM===NEW CAR TO ME==58M MILES==THREE TIMES IN THE LAST THREE MONTHS I HAVE COME TO A STOP LIGHT AND WHEN THE LIGHT TURNS GREEN AND I APPLY THE GAS THE CAR  WILL NOT MOVE AND ONLY WHINES. SOUNDS LIKE OTHER TRANSMISSIONS I HAVE HAD THAT WERE LOW OR OUT OF FLUID. IF I SHIFT DOWN TO 2ND IT TAKES RIGHT OFF AND CONTINUES WHEN I SHIFT INTO DRIVE. THE TIMES IT HAS DONE THIS THE CAR HAD BEEN DRIVEN FOR SOME TIME AND WAS WELL WARMED UP.
I DON'T KNOW IF THIS IS RELATED BUT SEVERAL TIMES IN THE 3 MONTHS I HAVE NOTICED SOME HARD DOWNSHIFTS. USUALLY JUST BEFORE YOU COME TO A COMPLETE STOP.
FLUID IS UP.

THANKS

Answer
Hello and thanks for the question...I'll try to help.
 It sounds almost like the low/1st gear servo is getting stuck in it's bore or that the seal for it is rolling over and letting fluid pass. Another thing is that the band that the servo applies might be burnt. What I would suggets is that you drop the pan and inspect what is in there.......looking for parts or fibers/metal/plastic.
Hope this helps,
Erik