I'm new to the 4x4 scene so I know a whole lot about this stuff. I have an 85 sr5 straight axle pickup with Auto locking hubs. I noticed my 4x4 didn't seem right I jacked all 4 tires off the ground and put it in 4wd. Back tires and front driveshaft spins but nothing else. So I took the locking hub off the passenger side and tried again, this time the axle shaft was spinning but when I grabbed it it stopped. Would that mean something is busted inside? Truck is stock, no welds or lockers.

 

Without a locker or some limited slip device inside the differential stopping one axle will simply transfer the power to the other axle. Sounds like your diffs are fine and it's the hubs that are the problem.

If your diff was broken you would know it. There would be very bad noises coming from it.

 

Thanks for the help! I'll get some AISINs manuals on the way.