singing trans

[wrenbirdx]

i got a 96 with a 5.2 i bought it for 800 dollors and alot of problems ive got everything fixed now minus the transmission it shifts perfect but it makes a zzzzzzzz sound while driving at low speed if i hit the gas and speed up it goes away after 20 minutes of driving it stops as well also at low speed it dosnt feel like it has any power i changed the filter and fluid (atf +4) and did a band adjustment so could this be the trans its self or the touqe converter?