Sick Defender - whirring noise

Hi Guys,
new to this site. I wonder if someone could give me a considered opinion on the following symptons::doh:
I have a 1999 Defender TD5

I have just returned from France. Whilst travelling the TD5 developed a strange whirring noise. It sounds like a dry bearing. I greased all of the appropriate nipples around the props and uj's, i have checked all of the oil levels.
It sounds/feels like it is coming from the vicinity of the transfer box. It cannot be neard when the clutch is pushed down. It can be heard when the props are being driven but is particulary noisy when at high speed you take your foot from the accelerator and let it slow down naturally.
I have checked the wheel hub bearings which are all cool. I thought about the thrust bearing but I believe this is only engaged when the clutch is pushed ???

Any advice/remedy would be most appreciated

many thanks

i would check porop joints again definately remove one end to see if seizing

is it lifted or got bigger wheels on it

No lift or bigger wheels. Is carrying some extra weight in the form of underbody protection, winch etc.....

Did you ever cure this problem? I have the same since my handbrake was worked on by backyard mech.

I have the same. Two different garages have suggested the gear box. One more specifically stated the lay shaft. Had the noise since purchase thought landy's made this noise naturally.
Will keep going until it lets go as second garage, who does a lot of landrovers, reckoned it will mean a reconn box and about £1000. My TD5 has 31k on the clock so think it will keep going for a few more 000k.
Off to France in June with crossed fingers!

Layshaft bearing rattle.

Mine does it too and the gearbox was rebuilt by the previous owner only a year ago


Its loudest when oil is hot and on slight over-run down from around 70-75mph.