i would go to manual hubs regardless. a 4:10 diff front is very easy to find. go check pirate. i bet you can get one for $50-75. i think i may still even have the one from my 4runner from when i upgraded to 4.56. it was non-ADD though, so you'd have to go with manual hubs.

Scott Landon
1995 T100 - total buildup underway
1988 4Runner (22RE, W56) - new DD
2005 Dodge CTD 4x4 - Tow Beast
1990 Spec Miata
2010 GT3
2013 E92 M3