Do you want disc or drum? LSD or open? There is a cutoff on the Explorer/Mountaineer for drums or discs. Finding the LSD 4.10 is a good one... I mostly see 3.73's at the boneyard.
Are you doing the work yourself or having somebody fab it up for you?
~Todd~ 2004 X 4.0 5 speed---SOLD
4" Lift, 4.56's, 33" Duratracs on M/T Classics
RR SYE, Tatton CV, MML, BL, TT, Dynomax Exhaust
Hella Lighting: Driving, Fogs and H4 E-Codes
... and NEVER will be