A904 front pump install problems 63 Dart GT

Hello after rebuilding my A904 I ran into problems installing the front pump, I torqued the bolts to the correct 20nm as specified but then after that I can't turn the input shaft and the output shaft can only be turned with a bar/ lever. I have the correct clearances in the clutch packs, I really don't want to go any further without knowing for sure what the issue is. any help would sure be appreciated!