Flat towing shouldn't be an issue, the auto hubs only engage when they receive power from the axles, otherwise they should be free, just like disengaged manual hubs.
For trail use it is best to swap to locking hubs, by design the auto hubs disengage momentarily before reengaging,also, it appears that the auto's have issues with wear or poor maintenance.
Write up for replacing the auto hubs w/manuals.Also, with flat towing, you will want to remove the drive shaft from the rear diff and hang it up, the trans doesn't lube itself with just the drive line spinning.