93 explorer a4ld

[ranger bob]

my 93 explorer used to be slow to shift on a cold day but fine when warmed up. Sold it to a lady, she flushed the transmission and then problems really began.To make it short, I took the thing back. Put it in reverse, it goes fine takes right off. Put it in drive or any other gear and you have to rev it up to 2500 rpm or so and bang it takes off. once moving it seems to shift fine. Ideas??