Parking brake/wheels turn

[Mertz]

I was trying to torque the rear axle nuts so I applied the parking brake figuring it would stop the drums from turning but the drums still turn. The drive shaft does not. The truck is off the ground with wheels off. I checked the ebrake and it is properly adjusted. Is my truck going to roll when the wheels are on and on the ground?  

[Merle Coggins]

The parking brake is on the tail shaft of the transmission to hold the driveshaft from spinning. When both wheels are on the ground then it'll hold the vehicle from rolling, unless one wheel is on ice, or something like that that allows it to slip and spin backwards. 

You may need to snug them up as much as possible and do final torque once it's back on it's wheels and on the ground. 

[kencombs]

Merle is correct.   The driveshaft won't turn, but the differential will allow wheels to turn if they don't both have traction.

[Sniper]

Now if you had a limited slip differential that theoretically wouldn't happen. Until you exceeded the slip torque value and then it would. But in your case since you haven't opened differential that's exactly what happens when both tires are in the air.