It could be the splines on your transmission tailshaft are so far gone that's what you're hearing.
But like Uncle Doug said, you're going to change that out (2 minutes=1 bolt) when you swap the transfer cases.
On the autos, the solenoid is mounted to the side of the shifter box.
The pin just projects in, and prevents the shifter handle from moving.
I just happened to slip with a cutting wheel and *removed* the pin. :D
Very obvious when you take it apart.
These solenoids are notorious for failing on...
My 91 RRC did this a year ago.
Ran fine, just random no start.
One time out of fifty.
Finally died once while running when I bumped the key.
I retrofitted a Carling Off-On-Momentary switch kit from Jason Lavender and it?s been fine ever since.