governor pressure sensor changed in 2000 from metal to plastic.
went from this
the lockup solenoid changed to match the new connector as well.
when i rebuilt my 46re, i had around $1k into it and have extra clutches in every pack, and added all the Sonnex hop ups as well.
otherwise for a stock rebuild you will spend around $250 for the kit.
its an easy trans to rebuild as well, the key is to take it apart as sub-assemblies and not as just a big mess of parts.