Td5 weird noise in 1st and 2nd gear

Hello
Today went for a drive to pick up my new winter tires, on the way home when taking off at a red light, a weird sound appeared in first and second gear, appears in first at low revs, stop when clutch depressed, when shifting in 2nd gear then the noise come back till 25km/h and then nothing. The sound only appears at a certain speed and under load, It seems to be coming from the gearbox differential area.
The truck has 246k Km, clutch replaced 4000km ago by a shop. truck always well maintained bought it at 200k
Here is a video of the sound

Let me know if you have any idea of whats causing that sound and if something bad and costly is coming up ...

well without being rude have you ran over any couple engaged in premarital relationship. Can happen. 1 and 2 gear tend to take alot of hammering over the years. Does this show up when engaged in low range too. Hopefully a better expert will land shortly so fingers crossed

It does it in low range but just once per gear like a squeak

First easy checks are UJs and handbrake