2000 Sport 4X4 Auto. trans. noises?

[tbirdman]

Just purchased a 2000 Sport with approx 28,000 kms( about 17,000 miles). After having driven it about 120 miles - I've noticed an annoying quiet buzz from the transmission ( I think ) when driving from a stop to about 35 mph. This buzz also seems to coincide with the shift from 2nd to Direct ( Drive). It doesn't happen all the time but it seems to be more prevalent when cold. Also- if entering a freeway on ramp and /or passing with auto.trans downshift on accleration ,this buzz seems to be present as well. The transfer case is of the auto-all wheel drive style ( Borg Warner). The noise can best be described as a buzzing solenoid. At freeway speeds in 5th or 4th with the overdrive shut off - the trans. is quiet. And- since it is an intermittent problem, for the most part driving is enjoyable. Has any one else experienced this problem ? I will be making a trip to the dealer for a test drive diagnosis. As of yet- I do not think any DTC's have been logged nor have I seen the MIL lamp illuminate.

Thanks for any info you have to offer or TSB's that may cover this problem.