87chev4x4

Just built a trans for my buddies 2000 rcsb pickup got it together with transgo hd 2 kit vette servo and 490 boost valve and longer pin in the servo for band apply it has been together for two months when first installed 1-2 shift very hard under part to full throttle now 1-2 shift is very very sloppy and if you stand on the throttle it will just bounce of the limmiter most of the time other times you will get a good firm shift !? I have built about three of these now and this is the only one that is having issues any ideas? Thanks for all help and info O and all other shifts are good and firm and fluid is not burnt ...... yet