Well, theres 2 types. Vac assist and "full time".
Each of those came in 4 gear ratios. (3.27, 3.55, 3.73 and 4.10).
The "full time" is essentially the same front axle design that was used on the Explorers thru 2005 and up thru 2009 on Rangers. (as far as I know)
Vac assist style has (of course) the vac assist module on the passenger side of the assembly and will not fit on a stock V8 Explorer. All V8 Explorers were either All Wheel Drive, or 2 Wheel drive, and had no use for the disconnect. The vac disconnect style was dropped in 1997 in favor of the "full time" style.
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