^ I agree with NIsaacs.
Just went through mine, because the planetary gear was shot.
My thoughts are unless you have the tools already, do not tear it apart. Need a heavy duty lock ring plier or those lock rings will be a pain. My biggest hurdle was the front shaft output needle bearing. Sunk into the case, no easy way to get out. Thought I was going to crack the case.
After adding up parts and tool cost, me rebuilding my own or buying the rebuilt was the same amount, without shipping or core.