I get some growling from down under gearshift area also - my guess is cold transmission getting itself lubed up as it sounds like dry gear teeth engaging and disengaging. However, the growl goes away within the first half-mile and is not getting any louder or lasting any longer (ie: getting worse).
I'm interested if any techs might know what this is, specifically. It's definately a linear-movement thing, noticeable at lower revs and keeps up with transmission speeds (not engine rpms).
1993 190 2.6 72k miles