No fluid in trans
no fluid in transfer case.
I know that exact sound you describe from experience...probably trans.
I won't say it means long term damage. 89 still has the bulletproof AMC I6 with the AX-5/Ax-15 tranny bolted to it.
Worst case scenario, it's a common trans and might cost you 500-600 to replace it used down the road, if, there is, in fact major damage from loss of fluid. That's an if.
Just curious what buyer is asking? I'm guessing 5K.