Sounds like you seriously rooted your diff. Just replace the entire thing. The drum to drum setup out of a AE71, AE86 and TE72 (in increasing strength) will all bolt in. Will need the tailshaft to match. Not sure about which hand brake cables to use. Sure it's been written somewhere.
Go to a wreckers and do it.
Hen
[EDIT - Just re-read and saw it is a KE70, not AE71, I assume the diffs are the same, but not 100%, check this out]