If it's a complete pump assembly that comes already assembled then you would be able to remove old one replace gasket and install new one. If your talking about relacing slide,vanes and rotor then thats a whole nother story.
I'm a novice in a big way when it comes to repairing trannies and with the help of HOTTOGO, or Mark if you will, he was able to walk me thru the process of changing my pump from non-lockup to lockup which required the pump to be removed.
With that said, just pay attention to detail when removing the pump and you'll be ok. Also as a side note there is a filter on the back of the pump, very small, so pay attention when that bad boy comes off.
Good luck and have some fun.
Frank
PS Mark your probably scratching your head thinking " when did I do that". Remember the confrence call one evening while I was driving home... I never did thank you for your help that night. So here it is. Thank You