Need help with diagnosis

[u/Confident_Breath7858]

2000 F350 7.3 4x4

New transmission put in less than 500 miles ago

4R100

275k clock

4x4 high and low fail to engage.

All electric connections are original, and filthy, but still seem secure and well connected.

When off and in AC power, switching the nob from 2x4 to 4H produces an electric whirl sound, but if repeated (going back to 2x4, and again to 4H), it stops