UPDATE !!!

Removed the R380 and opened it up. I think i found the issue. The primary pinion of the gearbox has had some teeth damage by the looks of it. It was brand new for Gods sake. OEM though. I have seen some crazy stuff on OEM (not Genuine) parts but that's way too messed. Have a look at the photo. It doesn't do justice to the extend of the damage. If you run your finger over it you can definitely feel a chip and cavity / gap. Its quite pronounced. Face hardening must have not been completed properly and even though the design is helical the force and pressure applied especially under load (the weight of the Disco) would cause it to produce the noise i think. Let me know what you think. Everything else was fine, be it bearings and synchros.
Cheers

I'd be tempted to say that there may have been a metal fragment causing that damage.

Hey there everybody,
GREAT NEWS AND UPDATE !
The issue was indeed the primary pinion and that damage it had. Gearbox all put back together (re-shimmed too - although it was just fine) and installed on the Disco. If you ever come across such a case, i hope that this thread helps you ! Many thanks to the LandyZone community for coming through with many suggestions and advice !
Have a great night everyone !

APOSTOLOS said:

Hey there everybody,
GREAT NEWS AND UPDATE !
The issue was indeed the primary pinion and that damage it had. Gearbox all put back together (re-shimmed too - although it was just fine) and installed on the Disco. If you ever come across such a case, i hope that this thread helps you ! Many thanks to the LandyZone community for coming through with many suggestions and advice !
Have a great night everyone !

Click to expand...

Gl@d you got it sorted well done.

That is indeed good news

Looks like I will have to curtail my use of the word definitely