I took the whol drive train out of my Blazer durring My body swap. when I seperated the trans from the motor I saw some wetness behind the tourque converter. Would this be from the front pump seal and how hard would it be to change that?
It is probably the pump input shaft seal (as you have noted), and that's pretty easy. Since you have it this far apart I would like to recomend that you change the filter and do any modifications now (shift kit, ect.).
Change the bushing too. Make sure there is not a groove worn into the converter hub.
The seal is not meant to hold off much fluid pressure. There is a drain hole between the bushing and the seal. When the bushing wears it allows more oil past then what can be returned through the drain hole. This of course puts too much on the seal to handle.