Driving towtrucks, through Triple A auspicious, the general consensus was it was okay for a short move under 35 MPH.
There's no lube fluid flow unless the engine is running, so that's the biggest problem. But if the engine has been running up to the point of needing a tow, it was generally considered acceptable.
On a barn find or 'hasn't run in 30 years' - not so much so.
If you have a 4wd the situation doesn't matter since the transfer case DOES have a rear pump (pthwwwtttt! to "you know who you are"!) so there should be no problem there either.
The differential(s) are ok whenever the ring gears fling 90wt ... so they're not gonna burn up. The front hubs a sealed, prelubed bearings and if they fail, they already were bad anyway.
In doubt? then flatbed tow it.