TD5 Gearbox Whine

[Budgie]

I've just got back from a trip to Northern Ireland (about 1000 miles in all) and during the return leg the R380 has developed a whine in 5th.
It's volume seems to be controlled by the revs/road speed as it's nearly gone when cruising but gets louder when you put your foot down.
The oil is at the correct level and is MTF94.

Before I ring Ashcroft's, has anyone else had this with their R380 and was it (as I suspect) the bearing on the gear, meaning a recon box that I really don't want to pay out for?

[Budgie]

To close this one: It was a knackered bearing in the gearbox, not sure whether it was the 5th gear bearing or on the main shaft.
Symptoms for others:
It started after a long drive, noticed that the box was reluctant to change down from 5th to 4th after a long stint in 5th and I had to put the stick into neutral before it would go into 4th. Then I noticed a very slight whine in 5th only but over the following two weeks the volume of the whine increased and before the box was changed I could also hear a low rumble in 4th as well.
These noises were more audible in Low range than in High but also with the T-box in neutral.

Speaking to Ian Ashcroft there was a thought that it could be coming from the t-box, which is more common on the TD5, but getting someone else to drive and putting a long screwdriver on the gearbox casing and sticking the other end on my ear, it was coming from the gearbox.

Over a grand later (including fitting) and it's back on the road.
Let's hope that's all that's wrong with this Disco as I don't want any more bills that size!!
It did got straight through it's MOT though!!  :D