Need help

It's probably the valve body has some crap in it........ I just did a shift kit in mine because I was having the same issue with mine after completely rebuilding the trans......... Made all the adjustments according to the shift kit ( I bought a Fairbanks kit, comes with extra springs and stuff, built it to street/strip specs), found the 2-3 shift valve was hanging up in the valve body....... Trans shifts great now!!!! Hopefully this helps.....