Transfer Box????

Hello all.
I have a 300tdi discovery.
I was driving it home on Sunday when suddenly it sounded like I was driving on a flat tyre. I stopped but everything seemed fine. I carried on driving a short distance but something was wrong. The drivetrain felt lumpy (best way I can describe it).
So far I have jacked the car up and checked the wheel bearings, half shafts, and prop shafts for play and they all seem ok. I have checked the oil levels in the diffs and transfer box and they all seem fine. I have also checked tyre pressures and again all seems fine.
I've just been on a short test drive and there is a whirring sound, like a dry bearing on deceleration. I have driven the car in high diff lock and the noise goes away. It's also not present in low box.
Any ideas what this could be??
Any help or pointers much appreciated.
Thanks.

check for play in front diff flange there shouldnt be any , if not try with one prop off at a time in diff lock high

Hi James.
My next step was to eliminate the props but if I drive in high diff lock the noise goes away.

it may do with both props on ,but with only one it may show if diff is poor ,another thing is to check to see if theres any endfloat in intermediate gear in t/box 30mm nut on rear cab be carefully tightened to remove it if there is ,youd have to remove sump plate to check can be resealed with silicone sealant instead of gasket if you want

I found the problem!!





New diff on order..