No Reverse and No Park

[crankdriven]

I apologize if this is covered by some other post, I have tried looking for this issue in past posts but I didn't find this exact issue.

I have had few Volvo's in the past and am familiar with most of the 2001 and 2002 XC70 transmission issues but this was a new one for me.

So I'm hoping you can help me with a transmission question on my current 2002 Volvo XC70. Early this spring I determined that there was no AWD. I determined that the right angle gear box was bad because I could spin the rear drive shaft while the car was in park. I went to the junkyard and pickup up a different gearbox. AWD was now functioning. About two weeks later, the car lost reverse and park. Found a wrecked car that was driveable. I drove it forward and reverse no issues. Swapped transmissions in to my XC70. My car worked good with AWD and all gears forward and reverse. Shortly there after, just like before....no reverse and no park. One thing I noticed is the car will not back up but you can hear the transmission shift into reverse and since there is a mechanical disconnect, when you move to park there is a grating noise until the spinning in the transmission stops and the park pawls engage. The other thing I found was that when the car is in reverse, the transmission is spinning the rear drive shaft (this blows my mind) with no movement at the wheels. Could this be a viscous coupling issue? I find it very interesting that this phenomena is happen to two transmissions back to back. Thanks for any help and insight you can share. Thank you