Assuming you don't have limited slip, which is rare, when turning an axle shaft coming out of the diff another shaft has to turn. In other words, if you turn the passenger-side shaft either the diff's input yoke or the driver's side axle will turn. And that is determined by how much resistance the shafts have.
If the t-case is in 4wd then the input yoke can't turn and the driver's shaft will turn. But if it isn't in 4wd then the input yoke will usually turn as the brake disk is usually dragging on the pads, causing more friction on the driver's shaft than the input.
In other words, you probably don't have a problem.
Gary, AKA "Gary fellow":
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Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI