Help w/noise diagnosis

[Michael Murphy <mmurphy@nais.com>]

Hi folks,
This noise just started on my 89 100 FWD, 3sp auto.
Note: LF driveshaft was rebuilt 2 weeks ago and new front tires were
installed a week ago (lugs were torqued correctly).

After driving about 2-3 miles, a metallic whirring almost whine appears
just above 30mph and seems to come from LF of car.  Only hear it under
acceleration or while maintaining speed (IOW when there is a load on
power train). The moment I back off the accelerator the noise stops.

Its level remains almost constant and pitch increases slightly as I
increase speed; remains constant while maintaining a set speed. Does not
increase/decrease when cornering and car tracks straight.  This is not a
wheel bearing or tire noise, I've BTDT with those types of noises on
this car.

Noise is not present when car is parked and engine revved - so that
makes me think it's not any of the "belt driven" devices.

Wondering if the axle rebuild is failing or God forbid the trans. is
going however AT fluid level/color/smell is fine?

Any help or ways to try to isolate this would be appreciated.
TIA,
MJ Murphy