If you're in Houston or DFW... one of the members on GMFS used to do gear installs on the side for $150 if you help and bring parts.

So maybe $500 in parts if you get a new eaton, install/rebuild kit, and some gears. then $150 to install. Just pick up some OEM used 3.73:1s, they're almost free and GM.

Just my 2¢