Outer Limits 4x4 Board

I have 2001 grand cherokee 4.7lt and have noticed a noise that occurs when shifting the auto lever from park to drive, park to reverse and between drive and reverse. Its a low buzzing noise i.e. you can hear it in the garage but not if your in the street. Transmission fluid is perfect in level and colourations, car has traveled 102 000kms. Any ideas?

It is a common thing for the GC.
I have the Overland and it does the same thing...
It`s the solenoid that makes this buzzing sound.
You can hear it when shifting to...not always.
Cheers,
Oli.