Well definely sound like the reverse gear of most cars but besides this sounds like something draging inside.
Yesterday noon driving back to home at around 40 celsius degrees 
, whe the traffic light was red, with the car stoped if I push the pedal clutch and engage first or secund gear the draging sound appear and fells, as the clutch was released and car beging to move, sound disappear (this sound is indepent to the straight first gear noise)
I am sure that the laygear shaft and gear of my car are the originals. I have around 10 years with my A prior that my Dad around 15 years and during this time this parts never been replaced, when my gearbox was revised few years ago, parts changed was: two syncrhos, input shaft, seals, gaskets and mount
Tomorrow I will take a video with my celular to record the noise and uploade it. I am doing planing remove engine to check the release bearing (heavy duty type)
Thanks